Preheat oven to 325 degrees F.
Whisk eggs, milk, salt and pepper in a large bowl.
Liberally coat a 12-cup muffin pan with cooking spray (or use silicone muffin cups).
Divide bell pepper, black beans, cheese and salsa among the muffin cups.
Top with the egg mixture.
Bake until set and lightly brown, 20 to 25 minutes.
Let stand for 5 minutes before removing from the pan.
