Place sweet potatoes in a large saucepan and cover with water. Bring to a boil and cook until fork-tender, about 15 minutes. Drain well, then puree in a food processor. Measure out 1 1/2 cups puree (discard any leftover or save for a different use). Place the puree in a small bowl, cover and chill in the refrigerator until chilled. (See notes)

In a large bowl, whisk together the flour, brown sugar, baking powder, baking soda, and salt. Using a pastry blender or clean fingers, cut the butter in until the mixture resembles coarse cornmeal with some pea-sized lumps of butter remaining.

In a separate bowl, whisk together sweet potato puree, buttermilk and maple syrup. Stir into the flour mixture until just combined. Switch to kneading the dough to finish bringing it together.

Turn out the dough onto a lightly floured surface. The dough should be sticky but workable. If the dough is too sticky, kneed in an additional 1-2 tablespoons of flour. Pat or roll the dough until it’s approximately 1-inch thick. Cut the biscuits using a 3-inch cutter. Re-roll the scraps as needed to cut the remaining biscuits.

Place the biscuits on the prepared sheet pan and brush with melted butter. Bake for 12-15 minutes, until fluffy and golden brown.