Cook pasta according to the directions on the package. Drain, reserving ½ cup of the starchy cooking water.
In a large skillet, melt 2 tablespoons butter on medium. Add black pepper and stir it around in the butter to toast it, 1-2 minutes.
Pour reserved cooking water into the skillet. Reduce heat to medium-low and add the parmesan, grana padano and pecorino romano. Stir until the cheese has melted and the sauce is thick.
Add remaining tablespoon of butter and stir until melted.
Add pasta to the sauce. Gently toss until the pasta is coated. Serve with more grated cheese and freshly cracked black pepper if desired.