Preheat the oven to 425° F. Spray an 8-inch or 9-inch round pan with a light coat of cooking spray and set aside.
Place flour in a large bowl. Use a pastry cutter, two knives, or a food processor to work the butter into the flour until the lumps are about the size of peas.
Slowly add ⅔ cup of buttermilk, and use a wooden spoon or spatula to stir until a soft dough forms. Add small amounts of buttermilk slowly, as needed, until the dough comes together. Stop stirring or pulsing as soon as you have a soft dough (be careful not to over-mix the dough).
Flour a work surface. Place dough onto floured surface and knead it once or twice. If the dough is sticky, feel free to sprinkle it with more flour, as needed.
Pat the dough out until it’s about ¾" thick.
Use a 3-inch round biscuit cutter to cut out the individual biscuits. Firmly press the cutter down into the dough, but do not twist. Twisting the biscuit cutter seals off the edges of the biscuits and they therefore will not rise as high. Arrange biscuits (with sides touching) in the prepared pan. Brush the tops of the biscuits with about 1 tablespoon of melted butter.
Bake for 16-20 minutes, or until they're a light golden brown.
Serve biscuits warm with gravy.