Step 1
Bring a large pot of salted water to a boil, then add the spaghetti and cook until al dente per the package instructions, about 10 minutes. Drain and set aside.
Step 2
Meanwhile, to a large skillet set over medium heat, add the oil and garlic. Cook, stirring occasionally, until light golden and fragrant, 2–3 minutes. Add the chile flakes and anchovy paste and cook until browned, about 5 minutes. Turn the heat to medium-low, add the butter, and stir until a smooth sauce forms.