To assemble Burritos : Spread 1 cup of ... bake at 350 degrees for 30 minutes. Add the peppers and onion and cook until the onion is translucent, 8 to 10 minutes. baked burritos with spicy sauce To make Sauce : Saute onion and garlic ... aside. For the salsa: Heat the vegetable oil in a large saucepan over medium heat.