Preheat oven to 350 degrees F (175 degrees C). Spray 12 muffin cups with cooking spray.
Heat a large skillet over medium-high heat. Cook and stir sausage in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and transfer sausage to prepared muffin cups.
Mix half-and-half, baking mix, eggs, salt, and black pepper together in a bowl; pour over sausage. Top each muffin with Cheddar cheese.
Bake in the preheated oven until cooked through and cheese is melted, about 25 minutes.