Preheat the oven to 400°.
In a large bowl, combine the flour, sugar, baking powder, and salt. Mix well.
Add the cold butter, and using a pastry cutter, mix everything until the dough looks like small pea-size balls.
Pour the buttermilk over the flour and butter, stirring slowly until the dough comes together.
Transfer the dough to a clean, lightly floured work surface. Knead the dough for about 10 minutes until everything comes together. Do not overmix
Use a rolling pin to press the dough into a flattened ball, and using a round cookie cutter, cut out the biscuits.
Place on a baking sheet and brush the top with melted butter, and baked until golden, about 20 minutes.
Serve with your favorite spread!