Preheat oven to 450 degrees. Line a baking sheet with parchment paper
In a large bowl, whisk together flour, baking powder, brown sugar, salt, cream of tartar, and cayenne pepper.
Scatter butter pieces over top of flour mixture and use a pastry blender to cut butter in until the mixture looks like coarse crumbs.
Stir in cheddar cheese and bacon crumbles.
In a separate bowl, whisk together milk and sweet potato until smooth.
Make a well in center of flour mixture and pour milk mixture into well.
Use a wooden spoon to stir just until combined.
Turn dough out on a well-floured surface. Gently knead about 12 times. Roll dough to 3/4-inch thick rectangle. Cut into 8 squares.
Place biscuits onto prepared baking sheet. Bake until lightly browned, about 12 minutes.