4 ounces cold unsalted butter (1 stick; 115g), cut into 1/4-inch pieces and refrigerated
1 1/2 cups all-purpose flour (8 ounces; 225g)
2 teaspoons baking powder
1 teaspoon (4g) kosher salt
3/4 cup (180ml) whole milk
Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper; alternatively, grease the baking sheet with butter.
In a large bowl, whisk together flour, baking powder, and salt.
Toss butter into dry ingredients until coated with flour. Working quickly, using your fingers or a pastry blender, rub or cut butter into flour until it resembles coarse meal. Alternatively, add flour mixture and butter to the bowl of a food processor and pulse 2 to 3 times to form pea-sized pieces; transfer to a large bowl.
Add milk and stir with a fork until the mixture just comes together into a slightly sticky, shaggy dough.
For small biscuits, use a teaspoon or a small cookie scoop to mound walnut-sized balls of dough onto prepared baking sheet. For large biscuits, use a 1/4-cup measuring cup to mound balls of dough onto prepared baking sheet.
Bake biscuits until golden brown, about 15 minutes for small biscuits and 20 minutes for large ones. Let cool slightly, then transfer to a wire rack. Serve warm or at room temperature.