Heat oven to 375°F. In large skillet, brown ground beef and onion until beef is thoroughly cooked. Drain. Stir in ketchup, sour cream, salt and garlic powder. Simmer 2 minutes.
Separate dough into 5 biscuits. Press or roll each biscuit into a 4x4-inch square. Place about 1/4 cup beef mixture on center of each square. Fold over one corner of each biscuit to form triangles; seal edges firmly with fork. Place on ungreased cookie sheet. Cut two 1/2-inch slits in top ofeach.
Bake at 375°F. for 12 to 18 minutes or until golden brown.