Preheat oven to 425. In a mixing bowl, whisk together dry ingredients including flour, baking powder, baking soda, and salt.
With a pastry cutter or fork cut-in small pieces of butter into the flour combination. This will make for a crumbly combination. With a wooden spoon, mix in the buttermilk. As you continue to mix, it will thicken to a mushy dough.
Lightly flour your workstation. Pour the contents of the bowl on the table. Sprinkle with a very light amount of flour if its too sticky. It may take a couple times or more kneading it out to see how sticky it actually will be. You want it sticky enough that it slighly sticks to your hand/spoon but can still flatten the dough without it sticking. Combine to make a round patty about 1/2 inch tall.
Using a cookie cutter or biscuit cutter (very important that it is sharp), make rounds and place them on a cookie sheet. Parchment paper is optional.
Brush regular milk on the top of the rounds for a nice golden brown look. Bake for 15-17 minutes. Eat warm. Save up to a week. Freeze up to a month.