From a Martha Stewart recipe circa 2001. Tried and true recipe and very simple.
4 cups all-purpose flour, plus more for work surface
4 teaspoons baking powder
1 teaspoon baking soda
1 1/2 teaspoons salt
1 teaspoon sugar
1 cup (2 sticks) unsalted butter, cut into pieces
2 cups buttermilk
Preheat oven to 375 degrees. Combine dry ingredients in a large bowl. Put 2 1/2 cups of the flour mixture into a food processor. Pulse in the butter all at once until they are pea sized pieces. Pour back mixture into large bowl, stir in buttermilk. It may be easier toward the end to flour your hands and mix it. Knead dough until it comes together and roll out into 1″ thickness. Cut into size desired. (Optional-prick tops of biscuits with the tines of a fork and brush with melted butter or milk or cream. Bake 18-20 minutes.