Preheat oven to 450° F.

Sift together 2 cups of the flour, baking powder, salt and sugar in a mixing bowl. Reserve the remaining 1/4 cup for later.

Using a pastry blender, work in the lard, butter or shortening until the mixture until the mixture resembles coarse crumbs. You can also pulse the dough in your food processor if you prefer.

Whisk together the mashed sweet potato with the buttermilk in a small bowl.

Make a well in the center of the flour mixture in your mixing bowl, and pour the buttermilk/potato mix into this. Use a spatula to gently mix the wet and dry ingredients together. If the mixture is very wet, add some of the remaining flour to adjust the dough. It should be tacky, but not overly wet.

Sprinkle some flour on your work surface and roll out the dough to about 1/2-inch thick and cut out with a biscuit cutter or suitable substitute.

Place biscuits on a parchment or silicone lined baking sheet. If the sides touch, they will have softer sides, as would they if they touch the sides of the pan. If you like crispier sides, leave them a bit apart.

Bake in a preheated oven about 12 minutes or until golden brown.

Serve biscuits warm, spread with butter and honey, or warm molasses, apple butter, or a dallop of homemade preserves.