Preheat oven to 450°F.
In a medium bowl, whisk together the flour, baking powder, granulated sugar, and salt.
Pour in the buttermilk. Stir until mostly combined, being careful not to overwork the dough.
In a small bowl, combine the melted butter, confectioners' sugar, honey, and cinnamon.
Pour the melted butter mixture into an 8×8-inch baking dish. Place the dough on top of the butter. Using a spatula (or your hands), evenly spread the dough out to the edges of the pan.
In a small bowl, combine sugar and cinnamon. Sprinkle over the biscuits.
Cut the unbaked dough into 9 equal squares (3×3 pattern). Bake for 28-30 minutes, or until the the biscuits are golden brown.
After removing the biscuits from the oven, allow the butter mixture to be absorbed.
Serve.