Generously salt a large pot of water. Bring to a boil. Add pasta and cook very al dente, about 2-3 minutes less than the pasta package instructions. (You will continue to cook the pasta in the skillet as you make the sauce.) Before you drain the cooked pasta, reserve 1 cup of pasta water.
Transfer drained pasta to a large skillet (12-inch non-stick is best). Add the butter and 1/2 cup of pasta water. Heat over medium heat until water starts to simmer. Reduce heat to low and add in Grana Padano and black pepper. Toss and stir pasta and cheese together. As the cheese melts continue to toss pasta with tongs and evenly coat it with sauce. Continue to heat until sauce slightly thickens and pasta is cooked.
Remove from heat. Toss in Pecorino Romano. If pasta looks dry, add a little more pasta water, a tablespoon at a time until the pasta looks glossy. Drizzle with high quality olive oil and garnish with more freshly ground black pepper. Serve immediately.
adapted from Martha Stewart Living Feb 2013