3sticks (¾ lb or 339 g)butter, cold and cut into ¼-inch slices
1¾cups (420 ml)buttermilk, cold(I prefer full fat buttermilk)
In a large bowl, whisk together flour, baking powder, baking soda, and salt.
Add the butter pieces and using either a pastry cutter or your hands (I like to use my hands), rub and flatten each piece of butter into the flour mixture until large bean-sized pieces remain.
Mix together buttermilk and eggs and pour into flour mixture.
Stir with wooden spoon until it comes together. You should not need more buttermilk, but if you do, only add 1-2 tsp at a time until the whole mixture comes together. It should be slightly wet.
Cover the bowl and place it in the refrigerator to chill for at least 30 minutes, or even overnight.
Preheat the oven to 400 degrees.
Remove the dough from the refrigerator. On a lightly floured surface, knead dough briefly, pressing and "smearing" the dough away from you onto the counter (called fraisage) with the palm of your hand. Roll or pat out the dough to about 1½-2 inches thick. Cut with a biscuit cutter.
Place the biscuits side by side (touching) in a large round baking pan, or any kind of bakeware that will fit the biscuits (a 9 by 13-inch rectangular pan will also work, or even a large baking sheet). Chill for 15-30 minutes while preheating the oven to 400° F.
Brush the biscuits with melted butter.
Bake for about 30-35 minutes, or until lightly browned and well risen.
Cool for about 5-10 minutes.
Biscuits freeze very well. You can wrap them individually, but it's not necessary if you place them in a freezer bag and then suck most of the air out of it with a straw (almost like using a food saver type of device to remove air). Place the biscuits in the freezer and store for up to 3 months.