1Heat oven to 375°F. Lightly grease cookie sheets with shortening or cooking spray. In large bowl, stir 1/2 cup powdered sugar, cream cheese, butter, shortening, vanilla and egg yolk with spoon until well blended. Stir in Bisquick mix until dough forms.
2On work surface sprinkled with additional powdered sugar, roll half of dough at a time to 1/4-inch thickness. Cut with cookie cutters. Use metal spatula to transfer cookie cut-outs to cookie sheets, placing cut-outs about 1 inch apart.
3Bake 6 to 8 minutes or until edges are light golden brown. Cool 2 minutes; carefully remove from cookie sheets to cooling racks. Cool completely, about 15 minutes. Spread frosting on cookies.