Bacalao con pimientos y cebolla is a traditional Spanish dish made with salted cod, bell peppers, and onions. The cod is soaked to remove the saltiness and then cooked with sautéed peppers and onions. The dish is flavorful and hearty, with the sweetness of the peppers and onions complementing the mild taste of the cod. It is often served with crusty bread or potatoes, making it a satisfying and delicious meal.