Preheat oven to 450°F. Grease a cast-iron skillet or a baking sheet.

Sift together flour, cream of tartar, baking soda and salt in a large bowl. Using a pastry blender or your fingers, cut butter into flour mixture. It should resemble coarse crumbs, with no large chunks of butter remaining. (If butter gets too soft, refrigerate mixture for 20 minutes.)

Make a well (or hole) in the mixture by pushing it up around the side of the bowl. Add the buttermilk ½ cup at a time, stirring just to moisten all ingredients. Dough should be soft and moist — don't over mix. Add remaining ¼ cup of buttermilk as needed, or discard.

Turn the dough out onto a lightly floured work surface. Knead gently until dough just holds together, about 10 times. Add more flour to sticky dough as needed.

Roll or pat dough into a square. Fold in half and pat flat again. Repeat 2 or 3 times to create flakes.

Cut biscuits with a 3-inch biscuit cutter a round glass or a knife. Place a cube of hoop cheese into the center and form into a ball quickly. Make sure cheese is entirely covered with dough.

Place biscuits into cast-iron skillet, touching. Lightly brush the tops with melted butter. Bake in center of the hot oven for 10 minutes. Remove from oven and brush with more melted butter. Bake for another 10 minutes, until golden brown and firm. Brush with more melted butter. Serve warm.