Step 1

Add 2 quarts water (8 cups) to a Dutch oven (or stockpot wide enough to fit spaghetti). The water will be very shallow because we want it to be very starchy. Cover and bring to a boil. Uncover and stir in salt then add spaghetti. Cook pasta until barely al dente (usually a few minutes less than package directions), stirring often so the spaghetti doesn’t stick. See next step to complete while pasta is cooking.

Step 2

While the pasta is cooking, melt butter with olive oil in a large skillet over medium heat. Add pepper, then cook for one minute. Set aside until pasta is done cooking.

Step 3

Once pasta is al dente, reserve 1 1/4 cups pasta water, then drain pasta in a colander and set aside.

Step 4

Slowly whisk in 1 cup reserved pasta water into the butter off heat. Let stand 3 minutes.

Step 5

Gradually whisk cheese into butter water a little at a time until combined. Turn heat to LOW and whisk constantly until cheese is completely melted and smooth.

Step 6

Add half of the pasta to the skillet and stir to coat. Add remaining pasta and toss until evenly combined, adding additional pasta water if needed to loosen pasta.

Step 7

Taste, and season with extra salt and pepper if desired. Serve warm.