Preheat oven to 425°F.
In a large mixing bowl, combine sugar, baking powder, salt, baking soda, and flour.
Whisk until combined
Grate or chop butter into small squares, and mix into dough until combined. If grating your butter, freezing it first will make grating easier.
Add buttermilk, mixing lightly until dough forms, but is still crumbly. Overworking the dough will make the biscuits less flaky.
On a floured surface, spread dough out until it's about 1 inch thick, then using a round cutting tool, cut out biscuits, and place on a pan lined with parchment paper.
Brush the tops of each biscuit with melted butter.
Bake biscuits for about 20 minutes, or until lightly browned on top.
Remove to cooling rack, let cool, then enjoy!