Preheat the oven to 425

Using an electric mixer, in a large bowl, whip sweet potato and milk until smooth.

Add the baking powder, salt, cinnamon, sugar and half of the flour to a food processor with the cut cubes of butter.(You can also do this step by hand with a pastry blender or two forks.)

Pulse 5-6 times, add the remaining flour, pulse to cut the butter in until mixture is crumbly.

By hand- gradually add the flour to the sweet potato, mixing in until a dough forms.

Turn the dough out on to a lightly floured surface and knead until smooth.

Roll out to around 1 inch thick and cut into rounds.

Place on a cookie sheet and bake for 12-15 minutes or until golden brown.

Brush with melted butter, sprinkle with cinnamon and sugar.