Step 1

Lightly oil or grease a 10-inch cast iron skillet, or line with parchment paper. Set aside.

Step 2

In a large bowl, whisk together self-rising flour and sugar.

Step 3

Use a pastry blender or two forks to cut in the cold butter until the mixture is crumbly and some pea-size pieces of butter remain.

Step 4

In a small bowl, whisk together mashed sweet potatoes and buttermilk. Stir the potato mixture into the flour mixture just until the dry ingredients are moistened. If the dough is too dry, add a little bit more buttermilk. If the dough is too sticky to work with, add a bit more flour.

Step 5

Turn out the dough onto a lightly floured surface. Gently knead 4-6 times.

Step 6

Press dough to 1-inch thickness.

Step 7

Using a round biscuit cutter dipped in flour, cut out biscuits and arrange in the cast iron skillet. Roll out the scraps once, and cut additional biscuits if necessary. Do not continue rolling and cutting or you may end up with tough biscuits.

Step 8

Place the skillet in the freezer for 10-15 minutes so that the dough can chill while you preheat the oven.

Step 9

Preheat oven to 450°F.

Step 10

Bake biscuits until golden brown and cooked through, about 15-20 minutes. Brush warm biscuits with melted butter and enjoy!