Roll out one of the pie crusts into a large rectangle on a lightly floured surface.
Brush the melted butter evenly over the entire surface of the dough.
Mix the granulated sugar and ground cinnamon together in a small bowl, then sprinkle it evenly over the buttered dough.
Starting from one long edge, tightly roll up the dough into a log, like you would a cinnamon roll.
Use a sharp knife to slice the log into 1/4-inch thick rounds.
Flatten each slice slightly with your fingers or a rolling pin.
Arrange the slices in a single layer in a greased 9-inch pie dish to form the bottom crust. Press and overlap the rolls slightly to make sure there are no gaps, making an even layer that rises up the sides of the dish. Chill in the fridge while you prepare the filling.