Chill fats: Place butter and cream cheese cubes in the freezer 10 minutes.
Mix dry: Whisk flour, baking powder, salt, and sugar in a large bowl.
Cut in fats: Using a pastry blender, cut butter and cream cheese into flour until pea-size crumbs remain.
Add wet: Beat egg, vinegar, and 3 Tbsp ice water; pour over flour mixture and toss to moisten. Add remaining water only if needed.
Knead: Turn out and knead 4–5 folds until cohesive. Wrap and chill 1 hour.
Roll & cut: Divide dough, roll ⅛-inch thick, cut 4-inch rounds, flash-freeze, and store in freezer bags up to 3 months.
