STIR TOGETHER FLOUR, BAKING POWDER, SUGAR, CREAM OF TARTAR AND SALT. CUT IN SHORTENING TILL MIXTURE RESEMBLES COARSE CRUMBS. MAKE WELL IN CENTER OF MIX; ADD MILK ALL AT ONCE. STIR UNTIL DOUGH CLINGS TOGETHER. KNEAD GENTLY ON A FLOURED SURFACE FOR 10 TO 12 STROKES. ROLL OR PAT TO A 1/2" THICKNESS: CUT WITH 2 1/2" BISCUIT CUTTER USING STRAIGHT MOTION. DO NOT ROTATE THE CUTTER. THIS WILL CAUSE BISCUITS TO FLATTER THAN DESIRED. BAKE ON UN-GREASED BAKING SHEET FOR 10 TO 12 MINUTES AT 450 DEG. F.