Make a mound 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, oil and pepper. Using a fork, beat together the eggs, oil and pepper and begin to incorporate the flour starting with the inner rim of the well.
As you expand the well, keep pushing the flour up to retain the well shape. Do not worry that this initial phase looks messy. 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 any leftover crusty bits. Discard these bits. Lightly flour the board and continue kneading for 3 more minutes. The dough should be elastic and a little sticky. Continue to knead for another 3 minutes, remembering to dust your board when necessary. Wrap the dough in plastic and allow to rest for 30 minutes at room temperature. Note: Do not skip the kneading or resting portion of this recipe. They are essential for a light pasta.
Roll out the pasta dough to the thinnest setting on a pasta machine. Cut the dough crosswise into 1/4-inch-wide strips. Place the tagliatelle on a sheet tray that has been dusted with semolina flour, cover with a clean dish towel, and set aside.
Bring 6 quarts of water to a boil and add 2 tablespoons of salt.
In a 12- to 14-inch sauté pan, cook the pancetta over high heat until it is browned and the fat has been rendered, about 10 minutes. With a slotted spoon, remove the pancetta to a plate lined with paper towels and set aside. Add the butter and parsnips and sauté over high heat without shaking the pan too much until they are golden brown and crispy, 5 to 6 minutes. Season with salt and pepper, add the parsley, and cook 1 minute longer.
Cook the tagliatelle in the boiling water until tender yet al dente, about minutes. Drain the pasta, reserving some of the cooking water, and add the pasta to the pan with the parsnips and pancetta. Toss over high heat to coat the pasta, adding pasta cooking water if necessary to keep the sauce from getting too tight. Divide equally among four heated pasta bowls, grate Parmigiano-Reggiano over each bowl, and serve immediately.
Mario Batali counts 25 restaurants, 11 cookbooks, numerous television shows and the 50,000-square-foot Eataly marketplace among his ever-expanding empire of deliciousness. His latest book is "America Farm to Table: Simple, Delicious Recipes Celebrating Local Farmers" (Grand Central Life & Style, 2014).