Boil the potatoes until fork tender. Drain and let cool for 5-10 minutes.
Mash the sweet potatoes well, add in the ricotta cheese, pepper and salt.
Stir in the flour 1/4 cup at a time. The dough should come together but not be dry. Mix until just combined.
Take about a 1/2 cup of dough and roll into a log 1" thick. Cut the gnocchi into uniform sized pieces about 1.5" long. Continue until all the gnocchi is made.
Bring a large pot of water to a boil. Add the gnocchi and cook for 2-4 minutes. The gnocchi will float when they're done.
In a large frying pan, melt the butter and add the sage. Add the gnocchi and don't flip until they get a crispy edge. Once the gnocchi is flipped, add in the garlic and cook until fragrant.
Serve the gnocchi with a sprinkle of parmesan cheese!