Cheesy Squash Custard Casserole

Prep: 15 min Cook: 30 min Serves: 8 Cuisine: American

A comforting casserole combining tender sautéed squash and onions with a cheesy custard topping, baked to perfection. The creamy Swiss and Parmesan cheeses add rich flavor, making it an ideal dish for family dinners or special occasions that appeal to vegetable lovers and cheese enthusiasts alike.

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Ingredients

  • 2 Tbsp. oil
  • 2 Tbsp. butter
  • 4 cups sliced squash
  • 1 cup chopped onion
  • 1 garlic clove, minced
  • 2 eggs, beaten
  • 1 1/2 cups grated Swiss cheese
  • 1/2 cup grated Parmesan cheese

Instructions

  1. Heat oil and butter in a large skillet.
  2. Add sliced squash, chopped onion, and minced garlic; sauté until vegetables are crisp-tender.
  3. In a bowl, combine beaten eggs, grated Swiss cheese, grated Parmesan cheese, dill, salt, and pepper.
  4. Transfer the sautéed vegetables to a buttered 8-inch square baking dish.
  5. Pour the egg mixture over the vegetables.
  6. Bake at 350°F (175°C) for 25 to 30 minutes or until set.

Tips & Substitutions

For a creamier texture, consider adding a splash of milk or cream to the egg mixture. If you don't have Swiss cheese, Gruyère or cheddar can be excellent substitutes. Fresh herbs like thyme or basil can elevate the flavor profile. If you prefer a spicier kick, adding a pinch of red pepper flakes can enhance the dish without overpowering it. Always taste your sautéed vegetables before adding them to the casserole.

Serving Suggestions

This Cheesy Squash Custard Casserole pairs beautifully with a fresh salad or crusty bread for a balanced meal. You might also enjoy it alongside grilled chicken or fish for added protein. For a comforting family dinner, serve it with a side of mashed potatoes or roasted vegetables. It’s a perfect side dish for a summer barbecue or a light vegetarian option for any gathering.

Storage & Reheating

To store leftovers, allow the casserole to cool completely, then cover it tightly with plastic wrap or transfer it to an airtight container. It can be refrigerated for up to 3 days. To reheat, place the casserole in a preheated oven at 350°F (175°C) for about 15-20 minutes, or until heated through. You can also microwave individual portions for a quick meal.

Nutrition & Diet Analysis (per serving)

Each serving of Cheesy Squash Custard Casserole contains roughly 677 calories, with 13g protein, 16g carbohydrates, and 63g fat. It is an excellent source of protein (26% of the Daily Value) and calcium (26% of the Daily Value), and a good source of vitamin A. Note that it is relatively high in sodium, at 1139mg per serving (50% of the Daily Value).

677 kcal 34% DV
Protein Fat Carbs

Macronutrients

Protein 12.9g 26% DV
Total Fat 62.5g 80% DV
Carbs 16g 6% DV
Fiber 0.6g 2% DV
Sugar 1.2g 2% DV

Electrolytes

Sodium 1139.2mg 50% DV
Potassium 115.3mg 2% DV
Cholesterol 174.1mg 58% DV

Vitamins & Minerals

Vitamin A 93.4mcg 10% DV
Vitamin C 0.2mg
Vitamin D 0mcg
Calcium 343.3mg 26% DV
Iron 1mg 6% DV
Diet fit Low-carb
Contains Milk Egg

Estimated from ingredients & per-serving nutrition — verify against package labels for allergies or strict diets.

* % Daily Values based on a 2,000 calorie diet (FDA 2020).

Frequently Asked Questions

Can I use frozen squash instead of fresh?

Yes, you can use frozen squash, but be sure to thaw and drain it well to avoid excess moisture in the casserole. Frozen vegetables can sometimes have a different texture, so sautéing them briefly before adding to the dish can help mimic the crisp-tender texture of fresh squash.

Can I make this casserole in advance?

Absolutely! You can prepare the casserole up to the point of baking and cover it tightly in the refrigerator for up to 24 hours. When you're ready to bake, simply pop it in the oven, adding a few extra minutes to the cooking time if it's cold from the fridge.

What can I do if I don't have Parmesan cheese?

If you're out of Parmesan cheese, you can substitute with Pecorino Romano or even nutritional yeast for a dairy-free option. While the flavor will differ slightly, these alternatives still bring a nice savory note to the casserole.

Nutrition is estimated from USDA FoodData Central ingredient data and may vary with brand, portion and preparation — see our methodology. This information is for general educational purposes only and is not medical or dietary advice (disclaimer).

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