Bring a large pot of lightly salted water to a boil over high heat. Add the gnocchi and cook until they float to the surface, 2 to 3 minutes; drain.
Melt the butter in a frypan over medium heat. Stir in the garlic and cook until the garlic has softened and is beginning to turn golden brown, about 4 minutes. Stir in the sage and salt for a few seconds then add the cooked gnocchi. Toss gently with 1/4 cup of Parmesan cheese and the pepper. Sprinkle with the remaining 2 tablespoons Parmesan cheese to serve.