Arrange the tater tots in a 9x13 inch baking dish coated with cooking spray.

Add the sausage to a large skillet and crumble with a fork. Cook over medium-high heat until browned and no longer pink. Transfer to a bowl with a slotted spoon and pour off all but two tablespoons fat.

Add the onion to the skillet and cook until softened, approximately 4-5 minutes. Stir in the peppers and cook for an additional 2-3 minutes.

Add the garlic to the onion mixture and cook for an additional 1 minute. Set aside.

In a large bowl, mix the milk, half-and-half, salt, pepper, cayenne, eggs, and half the cheese.

Sprinkle the sausage and onion mixture evenly over the tater tots.

Pour the egg mixture over the tots and sausage mixture, then top with the rest of the cheese.

Cover with foil and refrigerate for 30 minutes or overnight.

Preheat the oven to 350 degrees F.

Bake, covered, for about 25 minutes. Remove the foil and continue to bake until the cheese is brown and bubbly and the casserole is cooked through, another 20 to 35 minutes.

Allow the casserole to rest for 15 minutes.

Cut into squares and serve.