Bake the sweet potatoes at 400 degrees for about an hour or until tender.

When cool enough to handle, slip off the skins and mash the potatoes (or put them through a ricer). Bring a large pot of water to boil with a large pinch of salt.

Mix in the ricotta and parmesan cheese, nutmeg, salt and pepper.

Add half a cup of flour at a time, mixing it in until dough forms. It should be a little tacky (a little bit sticky, not completely dry) but not too sticky.

Form into a log onto a floured surface and cut into 6 even pieces.

Roll a piece out with hands to create a long 1-inch thick rope. Cut into 1-inch pieces and press along the back of a fork for grooves if desired. Dust with flour and put on a baking sheet. Repeat with remaining pieces of dough.

When the water has reached a boil, cook in batches, making sure they aren't crowded in the pot and that if they go to the bottom of the pot they do not stick. When they are fully cooked (about 5 minutes) they should be floating.Collect with slotted spoon and put onto another baking sheet. Repeat until all gnocchi are cooked.

In a large pan, melt butter over medium heat until it starts to brown and smells nutty. Add in sage leaves and turn off the heat. Divide the butter among serving dishes, top with gnocchi, pepper and parmesan chese for serving.