No two aglio e olio recipes are alike, but this one is pretty true to the classic method. The key is slowly toasting the garlic slices to a perfect golden brown in the olive oil. If it's too light, you don't get the full flavor and if it's too dark it gets bitter. My advice? Do it perfectly.
Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally until cooked through but firm to the bite, about 10 to 12 minutes. Drain and transfer to a pasta bowl.
While the pasta is cooking, combine olive oil and garlic in a cold skillet. Cook over medium heat to slowly toast garlic, about 10 minutes. Reduce heat to medium-low when olive oil begins to bubble. Cook and stir until garlic is golden brown, about another 5 minutes. Remove from heat.
Stir red pepper flakes, salt, and black pepper into pasta. Pour in hot olive oil and garlic, and sprinkle on Italian parsley and half of the Parmigiano-Reggiano cheese; toss until combined.
Serve pasta topped with the remaining Parmigiano-Reggiano cheese.
Notes
Recipe Tip
It's not traditional, but for extra richness, add 1 tablespoon butter when you toss pasta with cheese.