Preheat oven to 450F degrees. Spray a glass or ceramic 8x8-inch or 9x9-inch baking dish with nonstick cooking spray (I like the kind with flour in it).
In a microwave-safe bowl, melt stick of butter in the microwave. Pour melted butter into prepared baking dish.
In a medium bowl, mix together the flour, sugar, baking powder and salt.
Pour in the buttermilk. Stir until a sticky batter forms. If batter still seems too dry add a tad bit more buttermilk until the batter is thick and sticky.
Pour biscuit dough into baking dish (right on top of the melted butter.) Some of the butter will run over the top of the dough. Tip: I will spray my hand with some nonstick spray to help spread the dough out evenly in the pan.
Cut the dough into 9 squares (as best you can). This will help with cutting later when the biscuits are baked.
Bake (on the middle oven rack) for about 25-30 minutes, rotating dish once during baking.
Oven times DO VARY since different ovens have different hot spots, but basically biscuits should be golden brown on top and spring back to the touch. Insert a toothpick into the center. If it comes out clean with no batter, they are done!
If using unsalted butter, be sure to add 1 teaspoon of salt.
Eat within two days. Make sure to cover leftovers. If stored in the refrigerator, they will last for a week. These biscuits can also be frozen. Wrap well in freezer-safe plastic wrap and then store in a freezer-safe bag or container. Will freeze for up to 3 months.
Self-rising flour can replace the all-purpose flour in this recipe. Just do not add the baking powder and salt to the recipe as it is already included in self-rising flour.