Preheat your oven to 425°F (220°C). Yes, it’s hot—trust the heat to give you bakery-style texture.
Whisk flour, baking powder, salt, and sugar (if using) in a bowl. See? Dry ingredients behaving nicely already.
Cut in the cold butter with a pastry cutter or two knives until the mixture resembles coarse crumbs. Don’t overwork it; you want pockets of butter for flakiness.
Stir in milk just until the dough comes together. It should be a shaggy mess, not a sticky glue monster.
Turn dough onto a lightly floured surface. Gently pat or roll to about 1/2 inch thick. Resist the urge to overwork; tenderness is the goal.
Cut biscuits with a round cutter (or a glass). Place on a baking sheet about 1 inch apart. If you want tall, keep the edges clean by not twisting the cutter.
Brush with beaten egg if you’re fancy, then bake 12–15 minutes until the tops are golden. Listen for that satisfying crunch when you peek inside.
Cool slightly and serve warm. If you’re not devouring them immediately, wrap and store for later—they freeze well too.