Cinnamon Roll Biscuits

Preheat oven to 400°F. Line a quarter baking 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 or spatula until the dough starts to come together. Dump the dough out onto a clean work surface and continue to bring the dough together with your hands. Pat the dough somewhat flat with your hands and fold it over on top of itself. Repeat this 2 more times (this distributes the cold butter in the dough better to make flaky layers).
Flour the surface as needed to keep the dough from sticking, then roll it out into a large rectangle about ¼ 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 or unscented floss 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, milk and vanilla 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.