In a large skillet, heat 2 tablespoons of olive oil over medium heat until shimmering. Add one diced onion and three minced garlic cloves, cooking for 3-5 minutes until the onions are translucent and fragrant.

Stir in 1-2 teaspoons of cayenne pepper and sauté for an additional 1-2 minutes.

Pour in 2 cups of chopped tomatoes, stirring well to combine. Increase the heat slightly and cook for 5-7 minutes.

Gently nestle 1-1.5 pounds of firm white fish into the bubbling sauce. Cover the skillet with a lid and reduce the heat to low, simmering for 10-15 minutes.

Once the fish is cooked, remove the lid and let the sauce simmer for another minute. Transfer to a serving platter, and garnish with chopped cilantro and parsley.