1 1/4cupsbuttermilk*see notes for a buttermilk substitution
melted butter for brushing (optional)
Add the chopped bacon to a cold skillet and turn the heat to medium, stirring occasionally until browned (about 5 minutes). Set aside with the grated cheddar.
Preheat the oven to 425 degrees F. Line a large baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, sugar and salt.
Cut the cold butter into 1/2 inch cubes and add to the dry ingredients. Using a pastry cutter, a fork, or 2 knives, cut the butter into the flour mixture until the butter pieces are pea-sized. Stir in the cold buttermilk.
Knead the dough a few times to form it into a ball. Transfer the dough to a lightly floured work surface.
Using your hands, form the dough into a rough 1/2 inch thick square. Fold the square into thirds, like a letter, and press out into another square. Repeat the folding and pressing 2 more times.
Using a floured 2 1/2 inch pastry cutter, cut the biscuit rounds and place them on the prepared baking sheet. Press the dough scraps together to make more biscuits.
Bake in the preheated oven for 10-15 minutes until golden and flaky. Optional: brush butter onto the tops as soon as they come out of the oven, if you wish. Serve warm.
*If you don't have buttermilk, you can substitute 1 cup plus 3 tablespoons of milk mixed with 1 tablespoon of white vinegar.