Heat the oven to 400F and get out a large, light-colored baking sheet.
Sift the flours, sugar, baking powder, and salt into a large mixing bowl. Set aside. Using an electric mixer, beat the heavy cream in a medium-size bowl until it thickens, but not enough to hold soft peaks. Make a well in the dry ingredients, then pour in the cream. With a wooden spoon, stir briskly just until the dough coheres.
Turn the dough out onto a lightly floured work surface. With floured hands, knead the dough 3 or 4 times, then pat 3/4 to 1 inch thick.
Using a 2-inch biscuit cutter, cut the dough into rounds and transfer them to the baking sheet, leaving room between them. Gather the dough scraps and cut them into rounds as well.
Bake the biscuits until light golden brown, about 15 to 17 minutes. Transfer the biscuits to a cloth-lined basket and serve as soon as possible. Makes about 12 to 14 biscuits.