Make a well in the flour, add eggs and knead until smooth. Cover with a kitchen towel or a piece of plastic wrap and set aside to rest for 20 minutes.
Using a rolling pin or a pasta machine, roll the dough into paperthin sheets (1/8 inch or thinner). Dust with flour, fold several times on itself and cut into 1/8-inch strips with a knife. Lay out on a lightly floured baking sheet to dry.
Melt butter in a wide pan over medium heat, add sage leaves and sauté for a few minutes. Meanwhile, boil the pasta in a large pot of salted water and drain. Toss with butter and sage and garnish with the shaved truffle. Serve immediately.