This is one of my favorite fall recipes. Gnocchi may seems daunting at first but is incredible rewarding especially with brown butter and sage. The amount of flour make need to be adjusted depending, it's okay to add more if the dough is too sticky.
Preheat oven to 450 F
Arrange squash, cut sides down, in an oiled shallow sheet pan and put potatoes alongside. Roast vegetables until squash is tender, about 25 minutes. Transfer squash to a cutting board and potatoes to oven rack, then continue to roast potatoes until tender.
When cool enough to handle, scrape flesh from squash, discarding skin, then run through a food mill into a bowl. Remove skin from potatoes while still hot and force flesh through food mill into bowl with squash. Spread puree into a a shallow pan and cool.
Return purée to bowl and stir in egg, cheese,salt, white pepper, and nutmeg. Add flour, then gently knead dough by hand 1 minute (it will be soft and slightly sticky).
Turn dough out onto a floured cutting board and cut into 3 portions. Gently roll each portion into a long log about 3/4 inch thick. Cut each log into 3/4-inch pieces with a floured knife.
Press a piece of dough against tines of a floured fork and push with a floured thumb in a forward motion toward end of tines, letting gnocchi fall from fork onto a floured kitchen towel. Repeat with remaining pieces of dough.
Cook gnocchi in batches in 4 quarts of boiling water with 1 teaspoon of salt. Gnocchi are finished when they float to the surface.
Transfer to a baking sheet with 1 Tablespoon olive oil and toss to coat.
Melt butter in large saute pan until it just starts to brown and smell nutty, add gnocchi and let brown on each side. Add spinach, cranberries and sage. Season to taste. Finish with cheese.