Begin by mixing together the ravioli filling: In a small bowl, stir together the ricotta, truffle cheese, and egg.
Set up your pasta machine with the lasagna attachment on and add the flour.
Turn it on and add the liquid.
Lay the pasta sheets on parchment lined pans and cover with plastic wrap.
Cut each pasta sheet into two and a half inch wide rectangles, and top half with a teaspoon of filling. Paint the edges with the beaten egg white and press another cheese free rectangle on top. Press all around the edges with first your finger, and then a fork. Place them back on the pans and cover with plastic.
Bring a large pot of salted water to a small boil. Meanwhile make the sauce: In a large skillet melt the butter, and cook the mushrooms on medium heat until they're browned, for about ten minutes. Add the sage. Keep warm.
Add the ravioli to the barely boiling water. Simmer for about seven minutes. Drain and add to the sauce. Drizzle with the oil, and toss with the cheese.