These biscuits are a favorite of all ages in our family, from my young daughters to my mother-in-law (who requests them often). They are delicious, tender, and the festive color of a sunset. Great with a pat of butter at dinner, with berries for dessert or as a stand-alone snack. —kitchenwitchcookie
Preheat oven to 425 degrees F. Line a baking sheet with parchment paper or a non-stick liner.
Pierce each sweet potato with sharp knife once. Place potatoes on baking tray and roast for 30-40 minutes, until a sharp knife pierces through potatoes easily. When in doubt, bake for 5-10 minutes more. They should be as easy to cut through as butter.
Remove poatoes from oven and reduce oven temperature to 375 degrees F. Let potatoes sit until just cool enough to handle, but still hot. Scoop flesh from slightly cooled potatoes into mixer bowl. Mix on medium until pureed. (If large lumps remain or potato flesh is overly fibrous, it may help to run mixture through a food mill.)
Meanwhile, measure flour, sugar, salt and baking powder into separate bowl. Stir with a fork to combine.
Once potatoes are pureed, measure 1 3/4 cups of puree. (Set aside any remaining puree to add to pancakes, muffins, cookies, etc...) Place the 1 3/4 cups of puree back in mixing bowl with butter pieces, and mix on medium until the butter is melted and incorporated.
Add the dry ingredients slowly to the sweet potato mixture, until fully incorporated.
Turn dough onto large sheet of waxed or parchment paper. Place another sheet of paper on top and carefully pat dough into a rectangle that is even in thickness of 1-inch. Use well-floured 2 1/2-inch cookie cutters of any shape to create biscuits. Flour a pancake spatula or offset icing spatula to gently lift cut biscuits off paper and onto baking sheet lined with parchment paper, flipping to release if necessary. For square biscuits, simply cut large rectangle of dough into 2 1/2-inch squares with a floured knife or pastry cutter . Alternately, biscuits can be formed by dropping 1/4 cupfuls onto baking tray and flattening lightly with the measuring cup. Gather remaining dough, if necessary, pat to one-inch thickness and cut additional biscuits.
Bake biscuits at 375 degrees F, for 17-20 minutes, or until bottoms and edges begin to turn golden brown. Remove from oven and serve warm with butter.