Place the orzo, vegetable broth, oat milk, tomato sauce, mushrooms, cherry tomatoes, garlic, spinach, nutritional yeast, olive oil, salt, black pepper, and oregano into a large deep skillet. Cover with a lid and cook over medium-low heat for 6 minutes.
1 cup orzo, 1 cup vegetable broth, ½ cup oat milk, ½ cup tomato sauce, 1 cup mushrooms, thinly sliced, 1 cup cherry tomatoes, halved, 2 cloves garlic, minced, 2 cups fresh spinach, 2 tbsp nutritional yeast, 1 tbsp olive oil, ½ tsp salt, or to taste, ¼ tsp black pepper, or to taste, ½ tsp dried oregano