Begin by gathering all your ingredients.

Start by bringing a large pot of lightly salted water to a boil. Add the spaghetti and cook, stirring occasionally, until it's al dente—tender but still firm to the bite—about 10 to 12 minutes. Once done, drain the pasta and transfer it to a large serving bowl.

While the pasta is cooking, place the olive oil and sliced garlic into a cold skillet.

Set the skillet over medium heat and gently toast the garlic, allowing it to cook slowly for about 10 minutes. Once the oil begins to bubble, reduce the heat to medium-low. Continue to cook and stir until the garlic turns a golden brown, around 5 more minutes. Then, remove the skillet from the heat.

Sprinkle red pepper flakes, salt, and freshly ground black pepper over the cooked spaghetti.

Pour the hot garlic-infused oil over the pasta, then add the chopped Italian parsley and half of the grated Parmigiano-Reggiano cheese. Toss everything together until evenly coated.

Serve immediately, garnished with the remaining Parmigiano-Reggiano cheese on top.