Use a paring knife to peel celery roots, removing all blemishes. Slice paper thin on a mandolin, or sightly thicker using a knife. Place 5 or 6 slices on the bottom of each plate.
Dress arugula with extra virgin olive oil, lemon and salt and divide among each plate. Shave Parmigiano over each plate and then blanket with truffles or porcini, each sliced paper thin. Drizzle with remaining oil and serve.
Roll out pasta to No. 4 setting, roughly 1/8th inch thick. Cut pasta sheets into 4 inch long pieces and fold each in half. Cut roll into strips 1/2 inch thick. Take each piece between hands and roll back and forth several times to form a twisted piece. Set aside.
Bring 6 quarts water to boil and add 2 tablespoons salt.
In a 12 to 14 inch sauce pan, heat olive oil, onion and celery over medium high heat until soft, about 8 to 10 minutes. Add mushrooms and cook until sweated, about 8 to 10 minutes. Add tomato sauce and bring to a boil. Meanwhile, drop pasta into boiling water and cook 1 minute until soft. Drain well and toss into pan with mushrooms. Cook until wellcoated. Add parsley, toss into warm platter and serve.
Recipe Courtesy of Mario Batali