Bring 3 quarts of water to a boil in a large saucepan.
Add pasta and salt, stirring occasionally, and cook pasta for 2 minutes less than recommend cooking time on package. Strain pasta, reserving approximately 1 cup of pasta cooking water.
Melt 2 tablespoons of butter in large skillet over medium heat. Add pepper and cook until pepper is toasted, about 1 minute.
Add ½ cup of the reserved pasta water to skillet and bring to a simmer then add pasta and remaining butter.
Reduce heat to low and add Parmigiano Reggiano, stirring and tossing with tongs until melted. Remove skillet from heat.
Add Pecorino Romano, stirring and tossing until cheese melts and sauce coats the pasta. Pasta should be al dente. Note: Add more pasta water if the sauce isn't silky and you see unmelted cheese.
Serve pasta topped with a sprinkle of additional cracked black pepper and grated cheese.
Notes
1. Spaghetti can be substituted for bucatini.2. Use freshly finely grated cheese. Pre-shredded cheese contains additives to prevent clumping which can affect how it melts. 3. Fresh cracked black pepper is the signature flavor so do not substitute ground pepper.4. Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed. The nutritional value is only for the cacio e pepe and will vary based on the brand of pasta used. It does not include the nutritional value of any garnishes such as cheese. It does not include the nutrition for any substitutions.5. Be sure to check out the Key Ingredients along with the Recipe Tips and Notes sections found in the post, for more tips, options, substitutions, and variations for this recipe! You will also find step-by-step photos there.