Preheat the oven to 450 degrees F and grease a baking sheet.

In a large mixing bowl, whisk together flour, baking powder, baking soda, salt, and sugar.

Cut in the cold butter using your hands or a pastry blender until the mixture resembles coarse crumbs.

Stir in the mashed sweet potatoes and ground pecans.

Gradually add the half and half, mixing until a soft dough forms.

Lightly flour a clean surface.

Turn the dough out onto the floured surface and dust the top with flour.

Gently press the dough to 1/2 inch thickness.

Use a 2-inch biscuit cutter to cut out biscuit rounds.

Place the biscuits onto the prepared baking sheet.

Bake for 15 minutes, or until golden brown.