Impossible Mexican Fiesta Casserole

1 pound lean ground beef
Salt and pepper, to taste
4 ounces shredded Cheddar cheese (1 cup)
1 cup dairy sour cream
2/3 cup mayonnaise or salad dressing
2 tablespoons finely chopped onion
2 cups buttermilk biscuit baking mix
1/2 cup water
1 to 3 tomatoes, thinly sliced
3/4 cup green bell pepper, chopped
Paprika (optional)

Preheat oven to 375 degrees F. Grease a 13 x 9-inch baking pan.

Cook and stir the meat in a large skillet until brown. Drain off the excess fat. Season the meat with the salt and pepper; set aside. Mix the cheese, sour cream, mayonnaise and onion and set this mixture aside. Stir the baking mix and water together until a soft dough forms. With floured fingers, pat the dough into prepared baking pan, pressing the dough 1/2 inch up the sides of the pan. Layer the meat, tomato slices, and green pepper onto the dough. Spoon the sour cream mixture over the top and sprinkle with the paprika, if used.

Bake uncovered until the edges of the dough are light brown, 25 to 30 minutes. Cool 5 minutes and then cut into squares.