1 to 2tablespoonsmelted butter, for brushing on top
Whisk together the flour, cornstarch, salt, baking powder and sugar. Stir in heavy cream until a dough forms. Do not overwork. Turn the dough out onto a lightly floured work surface, and gently pat it into an 8-inch circle about ¾-inch thick. Use a sharp 2 ¼-inch biscuit cutter to cut rounds. Place them on a lightly greased (or parchment-lined) baking sheet. Gather the scraps and repeat cutting out biscuits.
Brush the biscuits with butter, if desired, for extra flavor.
Place the pan of biscuits in the freezer for 30 minutes. Preheat the oven to 425°F while the biscuits are in the freezer. Bake for 20 minutes until they are golden brown. Remove from oven and if any melted butter is left over, brush it on top of the baked biscuits. Serve immediately.