Preheat the oven to 400 degrees F. On a foil lined baking sheet, bake sweet potatoes until fork tender, about 40-50 minutes. Remove and allow to rest until cool enough to handle.
1/2 cup Parmigiano-Reggiano (freshly grated; plus more for garnish) 4 eggs (beaten) 1 teaspoon Fresh Nutmeg Salt 2 cups All-Purpose Flour (plus more for bench flour)
Cut sweet potatoes in half and scoop out the flesh into a large bowl. Mash until smooth. Add cheese, eggs, nutmeg, salt and about 2 cups of flour. Using a wooden spoon or hands mix until combined making sure not to over mix to avoid tough dumplings. Add more flour until dough is only slightly sticky to the touch. Divide the dough into four pieces. Roll the dough out into coil shape "ropes" and then cut into 1 inch pieces and set aside.
Bring a large pot of water to a boil and season with salt. Add the dumplings and cook until all of the dumplings float to the top.
1/2 cup Butter (1 stick) 1 Shot of Espresso (about 1 1/2 ounces) 3 tablespoons chopped Chives for garnish 1/3 cup Sour Cream
Heat a pan over medium heat and add the butter, cook until it begins to brown and add the dumplings. Add the espresso and toss to coat. Serve with chopped chives and sour cream.