In a bowl, add the flour, sugar, baking powder, baking soda, and salt. Whisk to combine.
Cut the butter into small cubes and put it into the flour mixture. With a pastry blender (or two forks) press the butter down to incorporate the butter into the flour. Work it in gently until the butter is mostly pea-size or smaller. The faster you do this step, the better. You want the butter to stay cold. (Note: this step can be done in a food processor instead)
Gently add the buttermilk and stir just until combined. DO NOT OVERMIX. Dough will be slightly sticky.
Dust a flat surface with a little more flour, dump out the dough and with a floured rolling pin, roll dough to 3/4 inch tall. Use a biscuit cutter, or the top of a glass cup to push straight down into the dough. Try to get about 5 or 6 biscuits cut, then gently put the scraps together (again being careful not to overwork the dough) and cut another 2-4 biscuits with the remaining dough.
Put biscuits 2 inches apart on the baking sheet lined with parchment paper and bake until barely golden, 10-13 minutes. Do not overcook.
Notes
*Note: makes 8-10 biscuits. If you make smaller biscuits they will cook much faster- so watch out to make sure they don’t burn.