Preheat the oven: Set it to 425°F and line a baking sheet with parchment paper.
Mix dry ingredients: In a large bowl, whisk together flour, baking powder, salt, and sugar (if using).
Cut in the butter: Use a pastry cutter, fork, or your fingers to mix the cold butter into the flour until it resembles coarse crumbs.
Add the milk: Pour in the milk or buttermilk and stir just until a shaggy dough forms.
Knead and fold: Turn the dough out onto a lightly floured surface, gently knead it 2–3 times, then fold it over itself 3–4 times to build layers.
Roll and cut: Roll the dough to about ¾-inch thick and cut biscuits using a sharp cutter. Press straight down—don’t twist.
Arrange on baking sheet: Place biscuits close together on the baking sheet for taller biscuits or spaced apart for crisp edges.
Brush and bake: Brush the tops with melted butter if desired, then bake for 12–15 minutes, or until golden brown.
Serve warm: Let the biscuits cool for a minute or two, then serve with butter, jam, or your favorite savory topping.