Preheat oven to 450. Mix flour, baking powder, cream of tartar, sugar and salt in medium bowl. Cut in butter with pastry blender of 2 knives until mix resembles coarse crumbs. Stir in cheddar cheese, add milk. Stir until mix forms soft dough.
Place on floured surface; knead 8 to 10 times or until smooth. Pat into 6 inch square. cut into 9 squares. Place on a greased baking sheet.
Bake 10 - 12 min. or until golden brown. Spread with Philly chive & onion cream cheese spread.