Bring a large pot of salted water to a rolling boil, then add the 10 ounces of dry fettuccine and cook until almost tender but still slightly firm to the bite (al dente).
Reserve a small cup of pasta cooking water, then drain the fettuccine in a colander.
Return the drained fettuccine to the pot and add the 4 ounces of butter and 4 ounces of half-and-half, then bring the mixture to a gentle boil over medium heat, stirring to melt the butter.
When the noodles are fully cooked and the sauce is combined, remove the pot from the heat.
Add the 1/2 cup grated Parmesan and cracked black pepper to taste, then toss thoroughly to coat the pasta; add a splash of reserved pasta water if needed to loosen the sauce.
Serve immediately while hot.
