Preheat oven to 500° F. Line a baking sheet with parchment paper and set aside.
In a large bowl, whisk together 4-½ cups flour, tbsp salt, and baking powder.
Slice butter into thin pieces. Take half of the sliced butter and work into the flour mixture by pressing together your fingertips. Then add the rest of the butter to the flour mixture and use your hands to mix all of the butter pieces into the flour. Mixture will resemble course crumbles; be sure not to overmix because some of the nice flat pieces of butter are what make these biscuits so buttery and flaky!
Pour buttermilk over the flour mixture. Using a spatula, gently fold flour and buttermilk together until combined.
Liberally dust the 1 cup of flour onto a work surface and gently turn the dough onto it, shaping the dough into a ball. Using a rolling pin, roll the dough into a rectangle about an inch thick. Fold the top third of the dough onto the middle third, and then fold the bottom third up over the middle and top third (like a letter!). Turn the dough 90 degrees and roll out again into a rectangle shape about an inch thick. Repeat the folding steps. Turn the dough 90 degrees again and repeat the rolling out and folding steps one more time.
Roll the dough out onto the floured surface (add more flour to the surface if needed), to about an inch thick. Dip your biscuit cutter in flour, then press straight down through the dough. Do NOT twist the cutter. Move the biscuit onto the prepared baking sheet. Using the tines of a fork dipped in flour, pierce holes into each biscuit.
Place baking sheet onto the middle rack and bake for 14 minutes, turning the baking sheet around halfway through for even baking.
Melt the 2 tbsp butter. Once biscuits are done, remove from the oven and use a pastry brush to brush the top & sides of each biscuit with melted butter.