Pizza Quinoa Casserole (Vegan!)
This casserole is the kind of weeknight meal that feels like a treat without a ton of fuss. It packs pizza flavors — tomatoes, Italian seasoning, melty vegan mozzarella — into a nourishing base of quinoa. The result is warm, comforting, and surprisingly light for something that tastes indulgent.
I love this recipe because it’s flexible and forgiving. You can make it oil-free, swap veggies, or assemble it ahead and bake when you’re ready. The steps are straightforward: cook quinoa, sauté vegetables, mix everything, bake. That rhythm makes it a reliable option for busy evenings or for feeding a small crowd.
If you’re meal-prepping or cooking for family, this casserole travels and stores well. It refrigerates and reheats without losing texture, and the flavors meld and improve a bit overnight. Below you’ll find the ingredients list, step-by-step directions exactly as written, and practical notes to help you avoid common slips.
What Goes In
At its heart this is quinoa joined with classic pizza profile ingredients: tomato sauce, Italian seasoning, garlic, basil, and vegan mozzarella. Vegetables — onion, bell pepper, mushrooms, spinach, and fresh Roma tomatoes — add body, moisture, and texture. The quinoa bakes up to a casserole that holds together and slices cleanly when cooled slightly.
Everything in this casserole plays a clear role. The quinoa is the structure and the main source of protein. Tomato sauce supplies acidity and brightness. Vegan mozzarella gives a melty, familiar finish. The Italian seasoning and fresh basil deliver that unmistakable pizza aroma.
Ingredients
- 1 cup white quinoa (uncooked) — the base grain; rinse to remove bitterness and to help it fluff.
- 1 yellow onion — provides sweetness and savory depth when sautéed.
- 1 green bell pepper — adds crunch and a mild pepper flavor; dice fairly small for even distribution.
- 8 oz. mushrooms — bring umami and moisture; slice or dice depending on preference.
- 4 cloves garlic — aromatic backbone; mince finely so it disperses through the casserole.
- 1 cup fresh baby spinach — wilts down into the mix for color and nutrients.
- 3 Roma tomatoes — diced and folded in for fresh tomato bursts and texture contrast.
- 15 oz. can tomato sauce — binds and flavors the quinoa; use plain tomato sauce (not pasta sauce) for a neutral base.
- 3/4 cup vegan mozzarella shreds* — for melty, cheesy texture; reserve a light handful for the top if you like a visible “cheese” layer.
- 2 tsp Italian seasoning — dried herb blend that provides the pizza-forward flavor.
- 2 Tbsp. fresh basil (for serving) — added after baking for a fresh, herbaceous finish.
Pizza Quinoa Casserole (Vegan!): Step-by-Step Guide
- Preheat oven to 375°F (190°C).
- Rinse 1 cup white quinoa under cold water in a fine-mesh sieve.
- In a saucepan, combine the rinsed quinoa and 1.5 cups water. Bring to a light boil, then cover, reduce heat to low, and simmer for 15–20 minutes, or until the water is absorbed.
- While the quinoa cooks, prepare the vegetables: dice 1 yellow onion, 1 green bell pepper, and 8 oz. mushrooms; mince 4 cloves garlic; chop 1 cup fresh baby spinach; dice 3 Roma tomatoes.
- Heat a large skillet over medium-high heat. Add the diced onion, bell pepper, and mushrooms and sauté about 7–8 minutes, stirring occasionally. (For a no-oil method, add about 3 Tbsp water as needed to prevent sticking.)
- Add the minced garlic, chopped spinach, and 2 tsp Italian seasoning to the skillet. Stir and cook 1–2 minutes more, until the garlic is fragrant and the spinach is wilted. Turn off the heat.
- When the quinoa is done, fluff it with a fork and transfer it to a large mixing bowl.
- Add the sautéed vegetables, 15 oz. can tomato sauce, 3/4 cup vegan mozzarella shreds, and the diced Roma tomatoes to the quinoa. Stir well to combine.
- Spread the mixture evenly into a 9×13-inch baking dish and gently press down. Sprinkle a light additional layer of the vegan mozzarella shreds on top if desired.
- Bake for 25 minutes at 375°F (190°C).
- Remove from the oven and garnish with 2 Tbsp fresh basil (chopped) before serving.
Why It’s Crowd-Pleasing
This casserole hits familiar pizza notes without the fuss of dough. People love the layers of texture: the slightly nutty quinoa, tender vegetables, and the stringy melt of vegan mozzarella. It’s an approachable plant-based dish that doesn’t announce itself as “healthy” — it just feels satisfying.
It’s also visually appealing. The bright red tomato sauce, flecks of green basil, and little bits of tomato give it an inviting color palette. That matters when you’re serving to family or guests who might be skeptical about quinoa or vegan cheese.
Finally, it’s flexible for dietary needs. It’s naturally dairy-free and can be made oil-free, gluten-free, and nut-free, covering a lot of bases for mixed groups. Those practicalities make it a reliable option for potlucks, weeknight dinners, or simple meal prep.
Vegan & Vegetarian Swaps
This recipe is already vegan, but if you want to alter textures or flavors, small swaps work well. If you prefer a richer mouthfeel, swap the vegan mozzarella for a dairy-based mozzarella (if you’re not vegan). For extra protein, stir in a can of drained chickpeas before baking.
Want more caramelized flavor? Roast the vegetables instead of sautéing them. If you need a lower-sodium option, use a low-sodium tomato sauce and skip any added salt when sautéing. For more heat, fold in red pepper flakes to taste.
Toolbox for This Recipe
Keep your prep efficient by pulling these tools together:
- Fine-mesh sieve — essential for rinsing quinoa thoroughly.
- Medium saucepan with lid — for cooking quinoa evenly.
- Large skillet — sautéing the vegetables; nonstick makes oil-free cooking easier.
- Large mixing bowl — to combine the quinoa and vegetables without spilling.
- 9×13-inch baking dish — the recipe’s specified size; fits the quantity for even baking.
- Fork or spatula — for fluffing quinoa and spreading the mixture in the dish.
Troubles You Can Avoid
Quinoa that’s gummy or undercooked is the most likely problem. Rinse the quinoa well to remove saponins, and ensure the water is fully absorbed before removing from heat. If it’s still a bit wet after the simmer, let it sit covered for five minutes and then fluff.
Overcrowding the skillet will steam the vegetables instead of sautéing them. Cook in a single layer when possible and give the pan a stir only occasionally. For an oil-free method, add a splash of water and lift stuck bits carefully.
Finally, avoid under-baking. The 25 minutes at 375°F both warms the filling through and allows the vegan cheese to meld. If your casserole seems very wet after baking, give it an extra 5–10 minutes; set it on a baking sheet to catch any drips.
Nutrition-Minded Tweaks
If you’re emphasizing nutrition, this casserole is already high in plant protein and fiber thanks to quinoa and vegetables. To boost protein further, fold in a cup of cooked lentils or a drained can of chickpeas when you mix the quinoa and veggies.
For lower carbohydrate content, increase the vegetable ratio and reduce quinoa to 3/4 cup cooked equivalent (note: follow cooking liquid adjustments accordingly if you change raw quinoa amount). Use a low-sodium tomato sauce to reduce sodium, or add extra herbs and spices to compensate for lower salt.
To increase healthy fats, drizzle a tablespoon of olive oil over the top before baking or stir in a couple of tablespoons of toasted pine nuts after baking for crunch and heart-healthy fats.
Chef’s Notes
Don’t skip the fresh basil at the end. It lifts the entire dish and gives a contrast to the baked tomato sauce. If you want a brighter finish, squeeze a teaspoon of lemon juice over the casserole after baking.
Vegan mozzarella brands vary widely in meltability. If your brand doesn’t melt well, mix half the shreds into the quinoa and sprinkle the rest on top; this warms the shreds within the filling and gives a more cohesive texture.
Leftovers taste great reheated, but the texture firms up as it cools. If serving chilled, let the casserole rest 15–20 minutes after baking to help it set and slice neatly.
Best Ways to Store
Cool the casserole to room temperature, then cover and refrigerate for up to 4 days. Reheat portions in the microwave for 1–2 minutes or in a 350°F (175°C) oven for 10–15 minutes until warmed through. If the casserole seems dry after refrigeration, splash a tablespoon of water or tomato sauce over the top before reheating to restore moisture.
For longer storage, freeze in airtight containers for up to 2 months. Thaw overnight in the refrigerator before reheating. Portioning into single-serving containers makes reheating faster and more convenient for lunches or quick dinners.
Common Qs About Pizza Quinoa Casserole (Vegan!)
Q: Can I make this gluten-free? A: Yes. The recipe is naturally gluten-free as written — just double-check your vegan mozzarella and tomato sauce labels for any additives if you have a strict sensitivity.
Q: Can I use brown quinoa instead? A: You can, but brown quinoa takes longer to cook and needs a bit more water. If swapping, cook per package directions and make sure it’s fully tender before mixing.
Q: How can I make this spicier? A: Add red pepper flakes while sautéing garlic or stir in chopped pickled jalapeños with the tomato sauce for a tangy heat.
Ready to Cook?
This Pizza Quinoa Casserole (Vegan!) is straightforward and adaptable. Gather your ingredients, preheat the oven to 375°F (190°C), rinse the quinoa, and follow the step-by-step guide above. Expect about an hour from start to finish — and a dish that’s cozy, flavorful, and easy to share.
If you try it, note one small change you made and how it turned out. That’s how this recipe becomes yours — small, practical tweaks that match your pantry and taste. Happy baking.
Pizza Quinoa Casserole (Vegan!)
Ingredients
Equipment
Method
- Preheat oven to 375°F (190°C).
- Rinse 1 cup white quinoa under cold water in a fine-mesh sieve.
- In a saucepan, combine the rinsed quinoa and 1.5 cups water. Bring to a light boil, then cover, reduce heat to low, and simmer for 15–20 minutes, or until the water is absorbed.
- While the quinoa cooks, prepare the vegetables: dice 1 yellow onion, 1 green bell pepper, and 8 oz. mushrooms; mince 4 cloves garlic; chop 1 cup fresh baby spinach; dice 3 Roma tomatoes.
- Heat a large skillet over medium-high heat. Add the diced onion, bell pepper, and mushrooms and sauté about 7–8 minutes, stirring occasionally. (For a no-oil method, add about 3 Tbsp water as needed to prevent sticking.)
- Add the minced garlic, chopped spinach, and 2 tsp Italian seasoning to the skillet. Stir and cook 1–2 minutes more, until the garlic is fragrant and the spinach is wilted. Turn off the heat.
- When the quinoa is done, fluff it with a fork and transfer it to a large mixing bowl.
- Add the sautéed vegetables, 15 oz. can tomato sauce, 3/4 cup vegan mozzarella shreds, and the diced Roma tomatoes to the quinoa. Stir well to combine.
- Spread the mixture evenly into a 9x13-inch baking dish and gently press down. Sprinkle a light additional layer of the vegan mozzarella shreds on top if desired.
- Bake for 25 minutes at 375°F (190°C).
- Remove from the oven and garnish with 2 Tbsp fresh basil (chopped) before serving.
Notes
*Oil-free option:
Omit vegan cheese shreds. Substitute with up to 1/4 cup nutritional yeast for cheesy flavor if desired. You'll also want to add salt to taste to enhance the flavors.
Originally published March 2013. Updated April 2023.
