Heat oven to 375°F. Place flour in medium bowl. Cut in butter, using pastry blender or crisscrossing 2 knives, until mixture is crumbly. Stir in 1 beaten egg until well mixed. Shape into a ball. Divide into 24 balls. Press 1 ball on bottom and up side of each of 24 ungreased small muffin cups, 1 1/4x1 inch.