Bring a large pot of salted water to a boil and cook the spaghetti according to package instructions until al dente; drain and reserve briefly.
Heat a skillet over medium heat and add the olive oil and melted butter until warm.
Add the minced garlic and sauté for 30–60 seconds until fragrant, taking care not to burn it.
Add the drained spaghetti to the skillet and toss to coat with the oil and butter.
Season with salt, ground black pepper, and red chili flakes to taste, then toss again to combine evenly.
Transfer to plates, garnish with finely chopped parsley leaves, and serve immediately.
