BISCUITS

2.5 cup flour (600 ml)

1/2 cup (112 g) soft butter
3 teaspoons baking powder
1 teaspoon soda
1 teaspoon salt
1 cup (240 ml) buttermilk

1 egg for glaze

Preheat the oven to 450°F. Combine the dry ingredients in a bowl. Flake the butter in the flour using a fork. Add the buttermilk, stirring with a fork, until clumpy. Turn out onto a floured surface, knead quickly 3-4 times. Pat flat , about 1" thick. Cut with a biscuit cutter. Arrange on a cookie sheet lined with a parchment. Glaze with the egg, using a pastry brush. Bake at 450°F until pale golden. Serve immediately.

UPDATE: if you don't have buttermilk, but you do have sour cream, your day is saved! Mix 1/2 cup sour cream with 1/2 cup milk or half&half and you have an approximation of buttermilk. The longer you let it sit at room temp, the better (up to 2 hours)