Gnocchi di Spinaci

3 pounds Idaho potatoes5 ounces spinach4 large eggs1 tablespoon salt1 teaspoon white pepper1 pound all-purpose flour1 cup parmesan, grated 1/4 cup butter4-6 sage leaves2 ounces reserved cooking liquid from gnocchiBring a large pot of water to a boil. Add potatoes, skin-on, and boil for about 30 minutes or until tender. Let cool; peel.While potatoes are cooking place spinach and eggs in food processor and puree.Place potatoes in large mixing bowl and add spinach puree, salt and pepper. While mixing, gradually add flour and parmesan. Combine well until it becomes dough-like.Take handful of dough, roll it out with hands into long rope 1-inch thickness. Slice off dumplings in 1/2-inch sections. Repeat until all dough is used.Bring large pot of water to a boil with a dash of salt; add gnocchi. Cook until they float, about 5 to 6 minutes. Drain, reserving 2 ounces cooking liquid for the sauce.In the meantime, for the sauce, melt the butter in a large sauté pan and add sage; saute 2 to 3 minutes but do not brown the butter. Add 2 ounces of cooking water from gnocchi and mix well. Add pasta to pan, toss well to coat. Season with salt and pepper if desired.Serves four to six.Chef Rodolfo Hernandez, I Gemelli, Addison