After five years in the South, I've learned to make a pretty good biscuit.
1 3/4 cups all-purpose flour,In a large bowl, whisk together flour, sugar, baking powder, salt, and baking soda. Cut the butter into small pieces and work it into the flour usint a pastry blender or two knives (I use my fingers) until mixture resembles coarse meal with some pea-sized lumps of butter remaining. Mix in the mashed sweet potatoes and then add the buttermilk; stir quickly into flour mixture until is barely combined. Don’t overmix.
2 tablespoons brown sugar
2 1/2 teaspoons baking powder
1 teaspoon salt
1/2 teaspoon baking soda
6 tablespoons chilled unsalted butter, cut into pieces
3/4 cup mashed sweet potatoes
Turn out dough onto a lightly floured surface, and work it very gently until dough comes together but is still slightly lumpy. If the dough is too sticky, add a little additional flour. Shape into a disk, and pat to an even 1-inch thickness. With a floured 2-inch biscuit cutter, cut out biscuits as close together as possible. Gather together scraps, and repeat to cut out more biscuits (do not reuse scraps more than once).
Preheat oven to 425. Arrange the biscuits on a baking sheet lined with a Silpat or parchment paper. Brush the tops with melted butter. Bake until golden, twenty-two to twenty-four minutes.