In a bowl, whisk together eggs and milk. Stir in black beans and pasta. Slowly add in the cooked veggies so they don't cook the eggs.
Grease a 13x9 inch baking dish with remaining ½ teaspoon olive oil. Pour pasta-egg mixture into baking dish. Transfer baking dish to preheated oven.
Bake for 20 minutes, and sprinkle with cheese. Bake another 15-20 minutes until cheese is bubbly and frittata is cooked through. Serve with salsa and avocados if desired.
Notes
*You can use any leftover cooked pasta. You'll use about 4 ounces (before cooking) or about 3 cups cooked pasta.*If using uncooked pasta for this dish, cook pasta first before sautéing the veggies. Slowly add in freshly cooked pasta, so it doesn't cook the eggs before transferring to a baking dish.