Preheat oven to 425 degrees. Place a cast iron skillet in the preheating oven.
In a large bowl, mix dry ingredients together.
Cut butter into pea-size pieces. Work shortening and butter into the dry ingredients until incorporated. It should resemble an oatmeal texture. Be careful not to over mix or the texture will be affected.
Pour buttermilk into mixture and mix with a wooden spoon or your hand until the flour is wet. The dough isn’t going to have form or shape at this point. Place dough onto lightly floured surface and fold on top of itself for about 1 minute. Roll or press dough to 1½ inch thickness. Cut into 3 to 4 inch rounds using a biscuit cutter or small mason jar.
Remove hot skillet from oven and place biscuits in the skillet making sure the biscuits are touching each other. Put a light thumbprint in center of each biscuit to keep them even when rising.
Place in oven for 20 minutes or until golden brown. Halfway through baking lightly brush with melted butter and bake for the remaining 10 minutes. Serve immediately.