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.