1. Stir together first 6 ingredients in a bowl.
2. Beat butter and next 3 ingredients at medium speed with an electric mixer until creamy. Add cream cheese, orange zest, and vanilla; beat until well blended. Gradually add flour mixture, beating at low speed until blended.
3. Divide dough in half, shaping into 2 flattened disks. Cover with plastic wrap, and chill 2 to 24 hours.
4. Preheat oven to 350°. Place 1 dough disk on a floured surface. Roll to 1/4-inch thickness; cut with a 4-inch star-shaped cutter. Place 1 inch apart on ungreased baking sheets. Repeat procedure with remaining dough disk.
5. Bake at 350° for 8 to 10 minutes or just until edges are lightly browned. Cool on baking sheets 3 minutes. Transfer to a wire rack, and let cool 30 minutes or until completely cool.
6. Spread cookies with a thin layer of Simple White Frosting; top with sprinkles.
Note: To make ahead, prepare recipe as directed through Step 5. Freeze cookies in a heavy-duty zip-top plastic freezer bag up to 1 month. Thaw completely at room temperature before icing.