Biscuits

I have been making these great biscuits for years, I can't even remember where I got this recipe..   1 1/3 cups all-purpose flour 3 Tbls. powdered milk 1 Tbls. granulated sugar 2 1/2 tsp. baking powder 3/4 tsp. salt 1/4 tsp. cream of tartar 1/4 cup butter-flavored shortening 2/3 cups buttermilk 1/4 cup melted margarine - divided

Stir together flour, powdered milk, sugar, baking powder, salt, and cream of tartar in a medium bowl. Cut shortening into dry mixture until well blended. Stir in buttermilk and 2 Tbls. melted margarine until well blended. On a floured surface, knead dough for 1 minute. Roll out dough to 1/2" thick, using a round biscuit cutter, cut out circles, place biscuits on an ungreased baking pan, or cookie sheet. Bake in a 450 degree oven for 10-12 minutes, until golden. Brush while hot with remaining melted margarine.