Cheesy Summer Squash And Zucchini Casserole Recipe

I swear my Easy Zucchini Casserole gets devoured before the main even arrives, thanks to that buttery cracker crunch and gooey cheese that turns garden squash into the star.

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I adore this Squash And Zucchini Casserole because it turns garden chaos into something people actually fight over. I love the gooey mess of shredded sharp cheddar cheese mixed with tender squash and zucchini.

I’m obsessed with that crunchy top of crushed buttery crackers, the Ritz thing that makes you do a double take. I call it my go-to Zucchini Casserole With Ritz Crackers and everyone assumes it’s fancy.

But it’s dumb-simple and honest, not slick blog fluff. And it smells like summer and garlic and butter.

I bring it to potlucks and watch forks disappear.

Ingredients

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Yellow squash and zucchini: mild, tender base that soaks up cheesy goodness.
Yellow onion: sweet, caramelizes nicely and adds cozy flavor notes.
Garlic: punchy little kick that makes it taste homemade and real.
Sharp cheddar: tangy, melty heartiness that makes you want seconds.
Monterey Jack or mozzarella: gooey stretch and mellow creaminess.
Parmesan: salty, nutty finish that adds some savory oomph.
Sour cream: creamy tang that keeps the casserole moist and rich.
Eggs: they bind everything so it slices cleanly, not sloppy.
Olive oil: helps veggies brown, adds light fruitiness.
Salt: brings out flavors, simple but totally necessary.
Black pepper: little heat and depth, nothing fancy but useful.
Dried thyme or Italian seasoning: herbal background, keeps it from tasting flat.
Crushed buttery crackers or breadcrumbs: crunchy topping that contrasts the soft interior.
Unsalted butter for crumbs: makes the topping gorgeously golden and crisp.
Fresh parsley: bright, fresh finish if you feel fancy.

Ingredient Quantities

4 cups thinly sliced yellow squash and zucchini combined (about 4 medium squash total)

1 medium yellow onion, thinly sliced

2 cloves garlic, minced

1 cup shredded sharp cheddar cheese (more if you like it cheesier)

1 cup shredded Monterey Jack or mozzarella

1/2 cup grated Parmesan cheese

1 cup sour cream

2 large eggs, lightly beaten

1 tablespoon olive oil

1 teaspoon salt

1/2 teaspoon black pepper

1 teaspoon dried thyme or Italian seasoning

1 1/2 cups crushed buttery crackers (about 1 sleeve Ritz) or plain breadcrumbs

4 tablespoons unsalted butter, melted (for crumbs)

2 tablespoons chopped fresh parsley (optional)

How to Make this

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1. Preheat oven to 375 F and lightly grease a 9×13 or similar baking dish with a little olive oil.

2. Put the thinly sliced squash and zucchini in a bowl, sprinkle about 1 teaspoon salt over them and let sit 8 to 10 minutes to draw out excess water. Then squeeze handfuls in a clean kitchen towel or paper towels to remove as much liquid as you can; you want them moist not soggy.

3. Meanwhile heat 1 tablespoon olive oil in a skillet over medium heat, add the thinly sliced onion and cook until soft and starting to brown, 6 to 8 minutes. Add the minced garlic for the last 30 seconds just to bloom the flavor, then take off the heat.

4. In a large bowl whisk together the sour cream, lightly beaten eggs, 1/2 teaspoon black pepper, 1 teaspoon dried thyme or Italian seasoning, and the 1 cup shredded cheddar, 1 cup shredded Monterey Jack or mozzarella, and 1/2 cup grated Parmesan. Taste and add a pinch more salt if needed.

5. Stir the squeezed squash and zucchini into the cheese and sour cream mixture, then fold in the cooked onion and garlic so everything is evenly coated.

6. Transfer the mixture to the prepared baking dish, pressing it down gently so it’s level and there are no big air pockets.

7. Make the topping by mixing 1 1/2 cups crushed buttery crackers or plain breadcrumbs with 4 tablespoons melted butter until crumbs are moistened and clump slightly. If you want extra crunch you can toss in a tablespoon of grated Parmesan.

8. Sprinkle the buttery crumbs evenly over the top, covering the surface. Pat lightly so they stick.

9. Bake uncovered at 375 F for 30 to 40 minutes until the casserole is bubbly around the edges and the topping is golden brown. Let rest 5 to 10 minutes after you take it out so it sets up a bit, then sprinkle with 2 tablespoons chopped fresh parsley if using and serve warm.

Tip: if your squash is extra watery you can roast the sliced pieces for 10 minutes first instead of squeezing, but squeezing works faster. You can also up the cheddar if you like it cheesier.

Equipment Needed

1. Ovenproof 9×13 baking dish (or similar)
2. Large mixing bowl (for the cheese, eggs and squash)
3. Medium bowl or colander for salting and draining the sliced squash
4. Skillet or frying pan for the onion and garlic
5. Cutting board and a sharp chef knife (for slicing squash, zucchini and onion)
6. Box grater or microplane (for the Parmesan and shredding cheeses if needed)
7. Measuring cups and measuring spoons
8. Whisk and a wooden spoon or spatula (for mixing and folding)
9. Clean kitchen towel or paper towels (for squeezing out excess water)

FAQ

Q: Can I make this ahead of time? A: Yes, you can assemble it up to 24 hours ahead. Cover and refrigerate the unbaked casserole, then bake straight from the fridge adding a few extra minutes to the bake time if it seems chilled through.

Q: My squash gets watery. How do I prevent a soggy casserole? A: Salt the sliced squash lightly and let it sit in a colander for 15 to 30 minutes, then squeeze out excess moisture with a clean towel or cheesecloth. That keeps the custard from getting too runny.

Q: Can I use different cheeses or make it lower fat? A: Sure. Swap cheeses like Colby, Gruyere, or a low fat cheddar. For lower fat, use low fat sour cream and part skim cheeses, but the texture and flavor will be a bit less rich.

Q: Is this freezer friendly? A: You can freeze the unbaked assembled casserole for up to 2 months. Thaw overnight in the fridge before baking. Baked leftovers also freeze fine for 2 months, reheat covered at 350 F until warmed through.

Q: Can I skip the crackers or use a gluten free option? A: Yes, use gluten free breadcrumbs or crushed GF crackers. You can also leave off the crumb topping for a lighter dish, though you lose that buttery crisp finish.

Q: How long should I bake it and how do I know when it is done? A: Bake at 350 F for about 35 to 45 minutes until bubbly and the top is golden. Insert a knife in the center to check set custard; it should come out mostly clean with a little moistness, not soupy.

Cheesy Summer Squash And Zucchini Casserole Recipe Substitutions and Variations

Cheddar cheese (1 cup)
- Colby or Colby Jack, 1 to 1, melts similarly and is milder
- Sharp white cheddar, same amount, if you want a tangier bite
- Gruyere, use slightly less (3/4 cup) for a nuttier, fancy flavor
- Vegan cheddar-style shreds, same volume, if you need dairy-free
Monterey Jack or mozzarella (1 cup)
- Provolone, 1 cup, melts smooth and adds mild smoke
- Mild white cheddar, 1 cup, for a bit more cheddar flavor
- Fontina, 1 cup, very melty and creamy if you can find it
- Dairy-free mozzarella shreds, 1 cup, for a dairy-free casserole
Sour cream (1 cup)
- Plain Greek yogurt, 1 cup, same tang and less fat
- Crème fraîche, 1 cup, richer and creamier if you want luxe texture
- Full-fat plain yogurt, 1 cup, works in a pinch but is a bit runnier
- Silken tofu blended with a splash of lemon, 1 cup, for vegan swap
Crushed buttery crackers or breadcrumbs (1 1/2 cups)
- Panko breadcrumbs, 1 1/2 cups, for an extra crisp top
- Crushed cornflakes, 1 1/2 cups, gives a sweet crunch and is gluten-free if flakes are
- Crushed seasoned crackers like Saltines, 1 1/2 cups, for more savory flavor
- Ground almonds or almond meal, 1 1/2 cups, for gluten-free and nutty crust

Pro Tips

1. Salt and wait, but not forever. Sprinkle the squash, let it sit 8 to 10 minutes, then squeeze well in a towel so the casserole isn’t watery. If you over-squeeze it’ll get kinda dry, so aim for moist not bone-dry.

2. If your squash is super wet roast it for 8 to 10 minutes instead of squeezing. Roasting concentrates flavor too, so you’ll get a nuttier taste. Just cool a bit before mixing with the egg-cheese base.

3. Don’t be shy with the sharp cheddar if you like it cheesy. Swap up to 1 1/2 cups cheddar and reduce the Monterey Jack a little for more bite. More cheese = richer texture, but too much can make it greasy so don’t go crazy.

4. Make the crumb topping extra crunchy: mix in a tablespoon of grated Parmesan and toast the cracker crumbs in a skillet with the butter for 3 minutes before sprinkling. That little pre-toast step gives a much better crunch than just melting butter on top.

5. Let it rest 5 to 10 minutes after baking and you’ll get neater slices. Also this reheats great next day; warm in a 325 F oven for 10 to 15 minutes so it heats through without drying out.

Cheesy Summer Squash And Zucchini Casserole Recipe

Recipe by Bob Jones

0.0 from 0 votes

I swear my Easy Zucchini Casserole gets devoured before the main even arrives, thanks to that buttery cracker crunch and gooey cheese that turns garden squash into the star.

Servings

servings

Calories

519

kcal

Equipment: 1. Ovenproof 9×13 baking dish (or similar)
2. Large mixing bowl (for the cheese, eggs and squash)
3. Medium bowl or colander for salting and draining the sliced squash
4. Skillet or frying pan for the onion and garlic
5. Cutting board and a sharp chef knife (for slicing squash, zucchini and onion)
6. Box grater or microplane (for the Parmesan and shredding cheeses if needed)
7. Measuring cups and measuring spoons
8. Whisk and a wooden spoon or spatula (for mixing and folding)
9. Clean kitchen towel or paper towels (for squeezing out excess water)

Ingredients

4 cups thinly sliced yellow squash and zucchini combined (about 4 medium squash total)
1 medium yellow onion, thinly sliced
2 cloves garlic, minced
1 cup shredded sharp cheddar cheese (more if you like it cheesier)
1 cup shredded Monterey Jack or mozzarella
1/2 cup grated Parmesan cheese
1 cup sour cream
2 large eggs, lightly beaten
1 tablespoon olive oil
1 teaspoon salt
1/2 teaspoon black pepper
1 teaspoon dried thyme or Italian seasoning
1 1/2 cups crushed buttery crackers (about 1 sleeve Ritz) or plain breadcrumbs
4 tablespoons unsalted butter, melted (for crumbs)
2 tablespoons chopped fresh parsley (optional)

Directions

Preheat oven to 375 F and lightly grease a 9×13 or similar baking dish with a little olive oil.
Put the thinly sliced squash and zucchini in a bowl, sprinkle about 1 teaspoon salt over them and let sit 8 to 10 minutes to draw out excess water. Then squeeze handfuls in a clean kitchen towel or paper towels to remove as much liquid as you can; you want them moist not soggy.
Meanwhile heat 1 tablespoon olive oil in a skillet over medium heat, add the thinly sliced onion and cook until soft and starting to brown, 6 to 8 minutes. Add the minced garlic for the last 30 seconds just to bloom the flavor, then take off the heat.
In a large bowl whisk together the sour cream, lightly beaten eggs, 1/2 teaspoon black pepper, 1 teaspoon dried thyme or Italian seasoning, and the 1 cup shredded cheddar, 1 cup shredded Monterey Jack or mozzarella, and 1/2 cup grated Parmesan. Taste and add a pinch more salt if needed.
Stir the squeezed squash and zucchini into the cheese and sour cream mixture, then fold in the cooked onion and garlic so everything is evenly coated.
Transfer the mixture to the prepared baking dish, pressing it down gently so it’s level and there are no big air pockets.
Make the topping by mixing 1 1/2 cups crushed buttery crackers or plain breadcrumbs with 4 tablespoons melted butter until crumbs are moistened and clump slightly. If you want extra crunch you can toss in a tablespoon of grated Parmesan.
Sprinkle the buttery crumbs evenly over the top, covering the surface. Pat lightly so they stick.
Bake uncovered at 375 F for 30 to 40 minutes until the casserole is bubbly around the edges and the topping is golden brown. Let rest 5 to 10 minutes after you take it out so it sets up a bit, then sprinkle with 2 tablespoons chopped fresh parsley if using and serve warm.
Tip: if your squash is extra watery you can roast the sliced pieces for 10 minutes first instead of squeezing, but squeezing works faster. You can also up the cheddar if you like it cheesier.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.