Prepare the pasta dough according to the recipe.
Soak the raisins in the rum to rehydrate. In a large bowl, beat the eggs and sugar together until the yolks are pale. Add the fontina, Parmigiano-Reggiano, hydrated raisins, and bread crumbs, mixing well. Add the citrus zests and mix well by hand. Set aside.
Roll the pasta out to the second-thickest setting on a pasta-rolling machine. Using a biscuit cutter or water glass, cut 3-inch circles from the dough. Spoon tablespoonfuls of the filling onto the center of half of the circles and top each filled circle with an unfilled circle, pressing to release any air bubbles before sealing the edges with moistened fingertips.
Bring 6 quarts of water to a boil and add 2 tablespoons salt.
In a small saucepan, heat the butter over medium heat to melt and warm it through.
Cook the krafi in the boiling water until tender and cooked through, about 6 minutes. Drain the pasta and turn out into a serving bowl. Drizzle the melted butter over, top with grated Parmigiano-Reggiano and serve immediately.
Mound 3 1/2 cups of the flour in the center of a large wooden cutting board. Make a well in the middle of the flour and add the eggs and the olive oil. Using a fork, beat together the eggs and oil and begin to incorporate the flour, starting with the inner rim of the well.
As you expand the well, keep pushing the flour up from the base of the mound to retain the well shape. The dough will come together when half of the flour is incorporated.
Start kneading the dough with both hands, using the palms of your hands. Once you have a cohesive mass, remove the dough from the board and scrape up and discard any leftover bits. Lightly reflour the board and continue kneading for 6 more minutes. The dough should be elastic and a little sticky. Wrap the dough in plastic and allow to rest for 30 minutes at room temperature.
Roll the pasta out on a pasta rolling machine to the desired thickness.
Recipe copyright 2001, Mario Batali. All Rights Reserved