Yellow Squash Spinach Casserole with Boursin
Creamy baked casserole combining tender yellow squash and wilted spinach in a savory milk-based sauce enriched with herbed Boursin cheese. The nutmeg adds warmth and complexity to this vegetable-forward dish. Ideal as a side for weeknight dinners or summer entertaining. This version builds a roux-thickened sauce directly in the skillet before transferring to the baking dish, creating a cohesive texture without layering.
Ingredients
- 2 tablespoon unsalted butter
- 2 tablespoon olive oil
- ½ cup onion, chopped
- 6 cup yellow squash, cubedzucchini1:1mild
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- 2 16 ounce package frozen chopped spinach, defrosted and squeezed dry
- 1 ½ teaspoon salt
- 1 teaspoon fresh ground black pepper
- ⅛ teaspoon ground nutmeg
- 3 tablespoon all-purpose flourcornstarch1:0.5gluten-freelightergluten-free
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- 2 cup milk
- 2 3 1/2 ounce package Boursin cheese, crumbledherbed goat cheese1.5:1 weighttangadds dairy
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Instructions
- 1
Coat a 13 by 9 inch baking dish with nonstick cooking spray.
- 2
Heat butter and oil together in a large skillet over medium high heat until butter is melted.
- 3
Add chopped onion and cook, stirring, until softened, about 3 minutes.
- 4
Add cubed squash and cook another 3 minutes, stirring a few times.
- 5
Stir in spinach, salt, pepper, and nutmeg and cook, stirring, until the mixture loses some moisture, about 5 minutes.
- 6
Stir flour into the squash mixture and cook until absorbed, about 2 minutes.
- 7
Add milk and Boursin, stirring until the mixture comes to a boil and cheese melts.
- 8
Transfer to the prepared baking dish.
- 9
Preheat oven to 350 degrees F.
- 10
Bake the casserole until the top is golden brown, about 20 minutes.
- 11
Let rest 5 to 10 minutes before serving.
Tips
Squeeze spinach thoroughly after defrosting to prevent a watery casserole. Pat dry with paper towels for best results.
The casserole can be assembled up to 2 days ahead. Cool completely, cover, and refrigerate. Bring to room temperature before baking to ensure even cooking.
Let the baked casserole rest 5-10 minutes before serving to allow the sauce to set slightly and make plating cleaner.
Good to Know
Cover and refrigerate up to 3 days. Reheat covered in 350F oven for 15-20 minutes until warmed through.
Assemble casserole completely, cool, cover, and refrigerate up to 2 days before baking. Bring to room temperature before baking.
Spoon into shallow bowls or plated alongside roasted chicken, baked fish, or grilled steak. Serves 6-8 as a vegetable side dish.
Common Mistakes
Do not skip squeezing spinach dry to avoid watery, separated sauce.
Do not skip the roux cooking step to avoid flour taste in the final dish.
Do not bake from cold without bringing to room temperature to avoid uneven cooking.
Substitutions
Gluten-Free Swaps
General Alternatives
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FAQ
Can I make this casserole ahead of time?
Yes. Prepare through the transfer step, cool completely, cover with foil, and refrigerate up to 2 days. Bring to room temperature and bake as directed. Do not freeze as the texture becomes grainy.
What if I don't have Boursin cheese?
Substitute with herbed goat cheese or feta, using slightly less as they are stronger. Alternatively, use cream cheese mixed with dried herbs like thyme and parsley. The casserole will be less herbaceous but still delicious.
How long does this keep after baking?
Refrigerate leftovers in an airtight container up to 3 days. Reheat covered in a 350F oven for 15-20 minutes until warmed through. Stir gently when reheating to redistribute the sauce.