I wanted to create a biscuit recipe that would result in amazing and super flaky biscuits. I really like working with my hands so perfecting this recipe was a really fun experience. Having your butter extra cold is the key here.
In a large bowl, mix the flour, baking powder, sugar, kosher salt and baking soda. Grate the frozen butter on the large holes of a box grater into the flour mixture and using your hands, start incorporating the butter into the flour mixture until you have pea-size chunks of butter in your dough. Add the buttermilk a little at a time and fold by hand to prevent overmixing. You want a shaggy dough that just barely holds together.
Flip the dough onto a lightly floured work surface and begin folding it on top of itself until it just comes together. Shape into a rectangle with the help of a bench scraper.
Roll the dough into a rectangle slightly larger than 6 by 9 inches. Begin folding the dough into a letter fold: first fold a third of the dough onto itself followed by the last third. Roll into a similar-size rectangle again. Continue with this step several times to create layers in your dough. Wrap with plastic wrap and let rest in the freezer for 30 minutes.
Preheat the oven to 425 degrees F.
Using a knife, cut the edges off all 4 sides of the dough rectangle so you have straight, perfect edges. Cut the dough into 3-inch squares. Transfer to a parchment paper-lined baking sheet. Using a pastry brush, brush each dough square with the schmaltz, bacon fat or melted butter and sprinkle with flaky sea salt.
Bake, rotating the baking sheet from front to back halfway through baking, until the biscuits are golden brown, 15 to 20 minutes.
