Preheat oven to 375 degrees. Put the rack on the middle shelf and place the second shelf near the top of the oven, for browning under the broiler at the end.
Bring a large pot of salted water to a boil and cook the pasta, al dente.
Meanwhile, in a large bowl, mix together the eggs, milk, salt and pepper. Add 1 1/2 cups grated Fontina, and 1/2 cup of Pecorino Romano cheese, stir to combine.
Heat a 10-inch cast iron skillet or oven proof skillet on medium-high heat.
Drain the pasta and rinse under cool water, drain well. Add the pasta to the egg mixture and stir to combine.
Add the butter and oil to the pre-heated skillet, to coat the bottom surface. Pour in the pasta mixture and spread evenly, pressing down the top just slightly to level it out. Cook 1 minute without stirring, turn off the heat.
Top with the remaining Fontina and Pecorino cheese. Place on the center rack in the oven, bake for 15 minutes or until the pie is set. For a browner top, move the pan to the upper rack and broil for 1-2 minutes. Watching carefully so that it doesn't burn.
Remove and let the pie sit for 5 minutes before cutting, or wait and serve it at room temperature. Enjoy!