Fill a large pot with lightly salted water and bring to a boil. Cook bucatini (or other long pasta) until just done.
Drain pasta, reserving 1 c. of the pasta water.
In a large skillet or in the same large pot, melt butter. Once butter is melted, add in fresh cracked pepper.
Let the pepper cook for a minute, then add in the pasta water and salt. Whisk to combine.
Toss in pasta, and stir to coat pasta. Then add in cheeses and toss to coat pasta.
Remove from heat and add in arugula. Toss gently and serve with more fresh grated cheese.