In a large skillet bring 6 cups of water and ¾ teaspoon of salt to a boil. Add the dry spaghetti and cook for two minutes less than the package directions call for.
Reserve a cup of pasta water before draining the spaghetti. Place the spaghetti in a bowl and set it close to the stove to keep it warm.
In the same pan you cooked the spaghetti, melt 2 tablespoons of butter with the black pepper over medium heat. Cook until fragrant.
Add ½ cup of the reserved pasta water to the pan and stir until a glossy sauce forms.
Turn the heat down to low and add the spaghetti to the pan. Top with the grated parmesan and the remaining 2 tablespoons of butter.
Use tongs to quickly mix the parmesan, butter, spaghetti, and pepper sauce until a creamy sauce forms. Serve immediately and garnish with additional pepper and parmesan cheese.
