In a large bowl, stir 2 cups shredded cheese, black beans, diced tomatoes with green chilies and green onions until combined.

In a separate large bowl, whisk eggs, milk, Bisquick, salt and pepper until well blended. Pour the egg mixture on top of the cheese-bean mixture; stir to combine.

Lightly grease the bottom and sides of a 13-by-9-inch pan with cooking spray. Pour egg mixture into prepared pan. Cover pan with plastic wrap and chill in refrigerator for 8 hours or overnight (no longer than 24 hours).

The next morning, heat oven to 350°F. Sprinkle remaining cup of cheese on top of egg mixture.

Bake 45 minutes until edges are golden brown and a toothpick inserted in the center comes out clean. Cool 5 minutes before slicing. Serve with sriracha or other hot sauce, if desired.