Sauté the chopped onions in olive oil until golden, making sure there is enough oil to fully cover onions.
While pasta is cooking in lightly salted water, gently add the anchovy filets to onions and press lightly with a fork until the anchovies are well mixed with the sautéed onions.
Toss spaghetti and anchovy mix together and ensure the spaghetti is well coated. Serve immediately.
Servings: 4