Preheat oven to 425 °F.
Line a baking sheet with parchment paper.
In a medium bowl, add the sugar to the flour and whisk until combined.
In another medium bowl, add the sweet potatoes to the heavy cream and whisk until combined, about 1 minute.
Add the flour mixture to the sweet potatoes and cream and gently fold to combine.
If the dough looks dry, add additional heavy cream one tablespoon at a time until the flour is moistened.
Lightly flour your work surface and fold dough over itself 3 or 4 times.
Press dough into 1-inch thick disk.
Cut out biscuits with a 2.5-inch cutter, make sure to press straight down.
Place biscuits on the baking sheet so they barely touch.
Optional: brush with milk or melted butter before baking for additional browning.
Bake for 15 to 20 minutes until tall and light golden.