Preheat oven to 375 degrees F. Grease a 3-quart rectangular baking dish; set aside. For crust, in a medium bowl, combine biscuit mix and cold water, stirring with a fork until biscuit mix is moistened and a soft dough has formed. Press mixture onto the bottom and 1/2 inch up the sides of the prepared baking dish. Bake, uncovered, about 12 minutes or until lightly browned.
Meanwhile, in a large skillet, cook ground meat over medium heat until brown. Drain off fat. In a medium bowl, combine sour cream, cheese, mayonnaise, and onion.
Sprinkle cooked meat over baked crust. Layer tomatoes over meat and sprinkle with sweet pepper. Spread sour cream mixture over ingredients in dish.
Bake, uncovered, about 30 minutes or until bubbly around edges. If desired, top with olives. Makes 8 to 10 servings.