To make your own self-rising flour, whisk all of the ingredients together in a bowl
use as directed in your recipe.
For the biscuits, preheat oven to 475°F. Spray a 10 1/2 inch cast iron skillet with nonstick cooking spray.
In a medium bowl, combine the self rising flour, baking soda, salt and sugar. Cut in the shortening and softened butter with a pastry cutter or fork until the lumps are pea size. Gently stir in the milk or buttermilk until all of the flour is incorporated
do not over mix. The dough should be very wet. If not, add more buttermilk to achieve a sloppy consistency. Let stand for 2 to 3 minutes.
Place all-purpose flour in a bowl. Spray an ice cream scoop or large spoon with vegetable spray and scoop out dough. Drop each biscuit one at a time into the flour. Using well-floured hands, pick up each piece and pass from hand to hand lightly to shake off excess flour and shape it into a soft round. Gently place the biscuits into the cast iron skillet. They should be a tight fit depending on the size of your skillet. Do not mash the biscuits down! Brush tops lightly with melted butter.
Bake at 475°F for 16 to 18 minutes. Cool before serving.
