
Think of this vegetarian enchilada casserole as a veggie-packed Mexican-inspired lasagna with corn tortillas standing in for the noodles! If your peppers are mild and you like heat, opt for spicy pico de gallo. This easy vegetarian dinner recipe is sure to become a new family favorite.
Preheat oven to 350 degrees F. Heat oil in a large skillet over medium-high heat. Add onion, poblanos and garlic; cook, stirring occasionally, until softened, 4 to 5 minutes. Add squash, zucchini, corn, pico de gallo and salt; cook, stirring occasionally, until the liquid comes to a simmer, 5 to 6 minutes. Simmer, stirring occasionally, until the liquid reduces by half, about 2 minutes. Remove from heat; stir in pinto beans and black beans.
Coat a 9-by-13-inch baking dish with cooking spray. Spoon one-third of the vegetable mixture into the prepared dish. Top evenly with 4 tortillas. Repeat with half the remaining vegetable mixture and the remaining 4 tortillas. Top with the remaining vegetable mixture. Sprinkle evenly with cheese.
Bake until the cheese is bubbly, 25 to 30 minutes. Sprinkle evenly with avocado and scallions. Dollop with sour cream.