Preheat oven to 450.
Cut sour cream into biscuit mix, add 7-Up. Makes a very soft dough.
Sprinkle additional biscuit mix on board or table and pat dough out. Cut in to 9 biscuits.
Melt 1/4 cup butter in a 9 inch square pan.
Place cut biscuits in pan and bake for 12-15 minutes or until golden brown.