Preheat oven to 300°F. Line a rimmed baking sheet with parchment paper.
Using a sharp knife, cut each tomato in half lengthwise. Arrange cut tomatoes on prepared baking sheet. Spray tomatoes lightly with olive oil or drizzle with olive oil. Sprinkle or brush on white balsamic vinegar and season with salt and pepper.
Place in preheated oven for 1 hour 10 minutes to 1 hour 20 minutes, or until soft and golden brown around the edges.
In a large frying pan, heat 1 teaspoon olive oil over medium-high heat. Add mushrooms and season with salt and pepper. Sauté until golden brown.
To assemble bowls:
Add ½ cup quinoa to bowl, followed by ½ cup to 1 cup baby spinach, ¼ cup ricotta, 4 tomato halves, and a spoonful of mushrooms. Drizzle with balsamic glaze and serve. Note: If some of your ingredients are chilled, microwave them briefly to warm them up.
If you prefer, the spinach can be sautéed. Add it to the mushrooms near the end of the cooking time to wilt the leaves.
Arugula or baby kale can be substituted for the baby spinach leaves.
Instead of ricotta cheese, try fresh mozzarella or feta cheese.
Don't have time to roast tomatoes? This bowl is great with fresh tomatoes, too.