Prep the Squash: Preheat your oven to 400°F (200°C). Cut the butternut squash in half lengthwise and scoop out the seeds. Place the halves, cut side down, on a baking sheet lined with parchment paper. Bake until tender, about 45 minutes. Once cool, scoop out the flesh and mash until smooth. Measure 1 cup
Prep the Potato: Peel and cube three or four large potatoes and cover them with water in a sauce pan over medium heat. When potatoes slowly fall off a knife when pierced, remove them from heat and pour cold water over them to stop cooking. Rice the potatoes in a potato ricer. Measure 2 cups
Mix the Dough: In a large bowl, combine the mashed squash, and riced potatoes, parmesan cheese, egg, salt, and nutmeg. Gradually knead in flour until dough holds together. If sticky, add more flour but keep the dough soft.
Form the Gnocchi: On a floured surface, divide the dough into smaller sections. Roll each section into a long rope, about 1/2 inch thick. Cut the ropes into ¾-inch pieces. Roll each piece over a gnocchi board (or the tines of a fork) to create ridges if desired.
Cook the Gnocchi: Bring a large pot of salted water to a boil. Cook the gnocchi in batches, allowing them to cook until they float to the surface, about 15-17 minutes. You may test when they begin to float, if not cooked to desired doneness, return to pan. Remove with a slotted spoon and transfer to a plate.
Prepare the Sauce & Serve: Melt butter with sage in a pot large enough to hold all the gnocchi. Once the butter begins to brown, add gnocchi and heat through. Transfer to a bowl and sprinkle with parmesan cheese.