Preheat the oven to 390°F. Bake the butternut squash on a baking sheet about 1 hour until tender. Scoop out the flesh (omitting the seeds) and mash until smooth. In a bowl, combine the squash (should be about 1½ cups), ricotta, a pinch of salt, white pepper, nutmeg, and flour. Make a well in the middle, add the beaten egg and combine the mixture with floured hands. Work until a smooth dough has formed. (Be careful not to overwork it, though.)

Cut the dough in half and shape each piece into a long cigar, about ½-inch thick. Using the back of a floured table knife, cut each length into 2-inch pieces to make the gnocchi. Gently make a dent in each one, which will allow the gnocchi to hold more sauce.

Add the gnocchi to a large pot of boiling water, tilting it from side to side briefly to prevent them sticking together. Simmer for 1½ to 2 minutes, until they start to float. Drain and leave the gnocchi to dry for 1 to 2 minutes.

Heat a frying pan over medium-high heat. Add butter and let it melt, cooking until it browns and has a nutty flavor. Add the gnocchi to the pan with a pinch of salt and black pepper and sauté for 1 to 2 minutes on each side until colored. Add the sage, and toss. Serve with grated parmesan.