If you’ve ever dreamed of combining all the flavor of your favorite pizza with the heartiness of a baked dish, this Vegetarian Pizza Casserole with Mushrooms and Peppers is the comfort food you didn’t know you needed. It’s cozy, gooey, and packed with all the classic pizza flavors—but with a twist. This dish is a satisfying casserole layered with saucy pasta, sautéed veggies, plenty of cheese, and a crispy golden top. It’s one of those casserole recipes for dinner that can please even the meat-lovers in your family, while being entirely meat-free. Whether you’re a fan of pizza hotdish casseroles or you’re simply looking for new pizza dinner ideas, this one’s worth baking.
Cheesy Vegetarian Pizza Casserole with Mushrooms and Peppers
Prep Time 20 minutes mins
Cook Time 35 minutes mins
Total Time 55 minutes mins
Course Main Course
Cuisine American, Italian
Servings 6 generous portions
Large pot To cook the pasta.
Large skillet For sautéing the vegetables. A non-stick or cast-iron skillet both work well.
Mixing bowls For combining the ingredients.
9x13-inch baking dish This size fits everything perfectly. You could also use a deep casserole dish or a lasagna pan.
Foil To cover during baking.
Oven Essential for baking and melting the cheese beautifully.
For the Casserole Base
- 12 oz rotini pasta or any short pasta like penne or ziti
- 2 tablespoons olive oil
- 1 medium yellow onion diced
- 3 garlic cloves minced
- 1 red bell pepper diced
- 1 green bell pepper diced
- 8 oz cremini mushrooms sliced
- 1 teaspoon dried oregano
- 1 teaspoon dried basil
- ½ teaspoon crushed red pepper flakes optional
- Salt and pepper to taste
For the Sauce
- 1 jar 24 oz of marinara or pizza sauce
- 2 tablespoons tomato paste for extra richness
- ½ teaspoon sugar balances acidity
For the Cheese Layer
- 2 cups shredded mozzarella cheese
- ½ cup shredded parmesan cheese
- 1 cup ricotta cheese adds creaminess
Optional Toppings
- Sliced black olives
- Diced tomatoes
- Fresh basil leaves
- Extra parmesan for topping
Cook the Pasta
Bring a large pot of salted water to a boil and cook the pasta according to the package directions, but stop about 1-2 minutes before al dente. It will continue to cook in the oven later. Drain and set aside.
Sauté the Vegetables
In a large skillet, heat olive oil over medium heat. Add the diced onions and cook for 2–3 minutes until translucent. Toss in the garlic, bell peppers, and mushrooms. Sauté for about 5–7 minutes until the mushrooms have released their moisture and everything starts to caramelize slightly.
Season with oregano, basil, crushed red pepper, salt, and pepper. The herbs are what give this dish that unmistakable pizza flavor.
Build the Sauce
Lower the heat and stir in the tomato paste and marinara sauce. Add a touch of sugar to balance the acidity, then let it simmer for 5 minutes. This thick, herby sauce is going to tie everything together.
Mix It Up
Preheat your oven to 375°F (190°C). In a large bowl, combine the cooked pasta, sautéed veggies and sauce. Mix in half the mozzarella cheese, half the parmesan, and all the ricotta. Stir until everything is well distributed.
Assemble the Casserole
Spread the mixture evenly into your baking dish. Sprinkle the remaining mozzarella and parmesan on top. If you’re adding black olives or diced tomatoes, now’s the time to scatter them over the cheese.
Bake and Broil
Cover the dish with foil and bake for 20 minutes. Remove the foil and bake for another 10–15 minutes until the cheese is melted and bubbling. For a golden brown top, broil on high for 2–3 minutes at the end—just keep an eye on it so it doesn’t burn.
Garnish and Serve
Let it cool for a few minutes before serving. Top with fresh basil or more parmesan if desired. It slices beautifully like a pizza pie recipe but has all the cozy vibes of a classic casserole.
Pairings
This vegetarian pizza casserole is hearty, cheesy, and packed with flavor, so it pairs best with lighter and refreshing sides. Here are some great options:
- Simple Arugula Salad: A peppery arugula salad with lemon vinaigrette cuts through the richness.
- Garlic Bread: Crunchy and buttery, it's perfect for scooping up saucy bits.
- Roasted Broccoli or Zucchini: For a roasted veggie companion that doesn’t compete.
- Sparkling Water with Citrus: A refreshing drink to balance the cheesy goodness.
- Iced Tea or Lemonade: If you want a non-sparkling, cooling drink.
This dish also works well with red wines like Pinot Noir or a chilled glass of sangria if you're making it for a more celebratory meal.
FAQs
1. What kind of mushrooms work best in this recipe?
Cremini mushrooms are ideal because they’re meatier and more flavorful than white button mushrooms. However, portobello mushrooms (chopped small) or even oyster mushrooms are great alternatives. Just be sure to sauté them thoroughly to prevent sogginess in the casserole.
2. Can I use another pasta shape?
Absolutely. While rotini is great because it holds sauce well, penne, rigatoni, or even elbow macaroni will work. Just avoid long noodles—this isn’t a pizza spaghetti casserole, although if you’re craving that vibe, spaghetti can definitely be swapped in for a fun variation.
3. What if I want a biscuit topping?
You can easily transform this into a pizza casserole with biscuits by layering canned biscuit dough on top before baking. Just bake uncovered for the full duration so the biscuits cook through and brown nicely.
4. Can I make this ahead of time?
Yes! You can assemble the entire dish up to 24 hours in advance and store it in the fridge, covered tightly with foil. When you’re ready to bake, let it sit at room temperature for about 30 minutes, then bake as directed. This makes it one of the best easy pizza casserole options for meal prepping.
5. Can I customize the toppings?
Definitely. Think of this as a pizza pasta bake casserole—just like pizza, you can add any toppings you love. Try chopped spinach, roasted eggplant, jalapeños, or even a sprinkle of crushed tortilla chips on top if you want to give it a fun twist similar to a Mexican pizza casserole.
