Heat the oven to 450 degrees F. Lightly coat a 9-inch straight-sided aluminum cake pan with lard and set aside.
Whisk together the flour, whole wheat pastry flour, baking powder and salt in a large mixing bowl. Add the lard and quickly rub it into the flour with your fingertips until the mixture resembles coarse crumbs. Blend in the buttermilk using a large wide spatula until the dough just comes together. The dough will be very loose and shaggy. Knead the dough in the bowl by folding it on itself 6 to 8 times.
Turn onto a lightly floured surface and pat into 1/2 inch thickness. Dip a 2-inch biscuit cutter into a little flour and press straight down, cutting as many biscuits as possible. Place the biscuits in the prepared pan so they are just touching each other and the pan. Fold together the remaining dough and repeat until you no longer have enough dough to form a biscuit. Press down lightly in the center of each biscuit with a fingertip. There should be approximately 15 biscuits, with some dough leftover.
Set the pan on the middle rack of the oven and increase the heat to 500 degrees F. Bake for 12 to 14 minutes or until the biscuits are just golden brown. Serve warm.