Heat oven to 350 degrees F. Spray a 9 x 13-inch baking pan.
Cook and stir ground beef and onion until beef is brown; drain.
Mix sour cream, ketchup, eggs and soup until well blended.
in beef mixture and mushrooms.
Mix biscuit baking mix and water until soft dough forms; beat vigorously
20 strokes. Press dough in bottom and 1 inch up sides of pan with
fingers floured with baking mix. Spread beef mixture over dough.
Bake until crust is light brown and beef mixture is set, about 25
to 30 minutes.