This simple squash casserole is exactly what it promises: easy to prepare, comforting, and naturally suited to a gluten-free diet when you choose gluten-free pasta sauce and cheese. It’s a great way to use the fresh squash from your garden or the market, and the finished dish is cheesy, light, and versatile.
I brought this to a recent church potluck and it was a hit with folks of all ages. It reheats well, travels easily, and can be adapted to whatever you have on hand—zucchini, yellow squash, a bit of onion, your favorite pasta sauce, and plenty of cheese.
Serve it alongside a simple protein or vegetable main course. It pairs nicely with plant-based burgers, grilled meats, or a crisp green salad for a lighter meal.
Super Simple Squash Casserole Recipe
Use this straightforward recipe as a base: you can keep it minimal or add layers of flavor. It’s forgiving, quick to pull together, and ideal for weeknights, potlucks, or holiday sides when you want something both homey and easy.
- Author: Elyse
- Prep Time: 15 minutes
- Cook Time: 20–30 minutes
- Total Time: 35–45 minutes
Ingredients
- 2–3 medium yellow squash or zucchini, trimmed and washed
- 1 small onion, thinly sliced
- 1 cup pasta sauce (choose a simple marinara or tomato sauce)
- 1–2 cups shredded cheese (mozzarella is mild and melts well; use your favorite)
Optional seasonings and add-ins: a drizzle of olive oil or a pat of butter for sautéing, a pinch of salt and pepper, minced garlic, chopped fresh herbs (basil, parsley, or thyme), or a sprinkle of grated Parmesan. These extras are optional and can be adjusted to taste.
Instructions
- Preheat the oven to 350°F (175°C). Grease a two‑quart casserole dish or lightly oil the bottom so the squash doesn’t stick.
- Slice the squash and onion into thin rounds, about 1/8 inch thick. Even slices help them cook through uniformly.
- Briefly sauté the slices in a skillet with a little olive oil or butter over medium heat until they are just starting to soften and release moisture. Alternatively, you can steam the slices for a few minutes. The goal is to remove excess water and avoid a watery casserole.
- Arrange the cooked squash and onion in an even layer in the prepared casserole dish.
- Pour the pasta sauce evenly over the vegetables. If using garlic or fresh herbs, you can mix them into the sauce before pouring.
- Sprinkle the shredded cheese over the top in an even layer. For a golden finish, add a little extra cheese or a light dusting of grated Parmesan.
- Bake at 350°F for 20–30 minutes, until the cheese is melted and bubbling and the edges are lightly golden. If you prefer a crisper top, broil for 1–2 minutes at the end, watching carefully so it doesn’t burn.
- Remove from the oven and let the casserole rest for a few minutes before serving; this helps it set and makes portioning easier.
- Serve warm. This casserole is a pleasant side dish for grilled meats, pasta, or plant-based mains, and it’s kid-friendly and adaptable for leftovers.
Tips and Variations
If you want a heartier casserole, stir in cooked grains such as rice or quinoa, or add a layer of cooked mushrooms or bell pepper. Swap the pasta sauce for a white sauce or a pesto for a different flavor profile. For a dairy-free version, use a dairy-free cheese or omit the cheese and finish with a drizzle of olive oil and fresh herbs.
To prepare ahead: assemble the casserole, cover, and refrigerate for up to 24 hours. Add a few extra minutes to the baking time if baking directly from chilled. Leftovers keep in the refrigerator for 3–4 days and reheat well in the oven or microwave.