From one of the great Joyce Goldstein's cookbooks (maybe Back to Square One, maybe Kitchen Conversations). I've made this dozens of times, including as a meatless Thanksgiving alternative. It's reliable and good. It's easy to prepare the dough in advance, then just cook when ready to serve. Be sure to drain and warm the puree to dry it out or it will require up to 2 more cups of flour to reach the right consistency. Trust me on this.
- If you're using homemade puree, put it in a strainer and let it drain for at least 30 minutes. Then warm the puree in a pan to evaporate any excess moisture.
- Combine puree, egg, salt, pepper, nutmeg and enough flour to form a dough that holds together. Knead a few times, adding more flour if needed to make a non-sticky dough.
- Form dough into a long roll (or two) about 1 inch across. (At this point, you can dust it with flour and wrap in plastic wrap to refrigerate for later.).
- Bring a large pot of water to a boil. Cut off about 1/2-inch segments of dough. (We don't bother to shape them.) Boil about 8 to 12 gnocchi at a time. They're ready when they float to the top. Remove to a bowl.
- Heat the butter in a saute pan. Add the sage leaves and hazel nuts. Toss lightly with the gnocchi. Top with Parmesan and mix gently.