1. Pre-heat over to 425. Roast sweet potatoes 45 minutes or until tender. Cool. remove pulp and mash. (You should have about 1 cup.)
2. Combine flour, salt and baking powder. Cut butter into flour mixture, some chunks of butter are welcomed. Add the sweet potato puree and half of the buttermilk to the flour mixture. Fold it in with a wooden spoon until dough begins to pull away from the sides of the bowl. Add more buttermilk if needed to finish binding the mixture. Dough should be moist, not wet.
3. Dust your workspace and begin to form dough into a ball. Fold over 6 times, dusting with flour in-between each time. Roll out dough about 3/4 of an inch thick and cut out circles or squares. Brush tops with a mixture of 2 tbsp melted butter and whole buttermilk. Let cook for 8-12 minutes depending upon your oven.