Whisk together the flour, yeast, sugar, baking powder, salt, and baking soda.
Add the cold butter, and mix with a pastry blender or a fork until crumbly.
Heat the buttermilk and water in a saucepan or the microwave to 100-110°F. (The buttermilk may separate a bit as it heats.)
Add the buttermilk mixture to the flour mixture, and stir just until the dry ingredients are moistened.
Cover the bowl with plastic wrap, and refrigerate for at least 2 hours (up to 5 days).
Preheat oven to 400°F (200°C).
Line a half sheet pan or 9"x 13" pan with parchment paper.** Alternatively, use a cast iron skillet(s).
Transfer the chilled dough onto a lightly floured surface. Knead 3 or 4 times.
Gently roll the dough into a 1/2-inch thick circle. Fold in half and repeat, rolling the dough again to 1/2-inch thick. Use a 2-inch round cutter to cut out the biscuits. Re-roll the remaining dough once and continue cutting.
Place the biscuits with the sides touching in the prepared pan(s).
Brush the tops of the biscuits with 2-3 tablespoons of melted butter.
Bake 15-20 minutes, or until golden. Remove from the oven. Brush warm rolls with more melted butter before serving or serve with butter on the side.
Video
Notes
*If you want to use active dry yeast instead of instant, combine it with the water (100-110°F) and let it stand 5 minutes as a first step. Then add the yeast mixture along with the buttermilk (you won't have to heat the buttermilk) in step 4.
**A 9"x 13" is a tight fit, but I like the way the biscuits bake in that size pan. A half sheet pan is a safer choice for those of you that are really efficient in your biscuit cutting. Or place any extra biscuits on a small separate pan if you run out of room.