Preheat oven to 425°F. Line a half sheet pan or 9x13-inch baking pan with parchment paper or grease with nonstick spray.
In a large bowl combine the flour, baking powder, baking soda, salt and sugar. Add the butter and cut into the dry ingredients with a pastry blender until butter is the size of small peas. Add the buttermilk and mix with a spoon and then your hands to bring it together into a ball.
On a lightly floured surface, roll the dough out into a large rectangle about 1/2 inch thick.
Spread with the melted butter, then sprinkle with the sugar and cinnamon. Starting with one long side, tightly roll up the dough until you have a long log. Use a sharp knife to cut into 12 rolls.
Place the rolls on the prepared pan. Bake until rolls are golden brown, about 18-20 minutes. Let cool slightly.
Whisk together the powdered sugar and milk to make a thick but pourable icing. Drizzle over the biscuits while they're still warm. Biscuits are best served the day they are baked.