Heat 2 tablespoons olive oil in a saucepan over medium heat. Add garlic and sauté for 1 minute or until fragrant. Add grape tomatoes, salt and pepper and cook for 5 minutes.

Add chopped onions, crushed tomatoes and sliced olives; cook for a few more minutes or until onions softened. Adjust the seasoning.

Meanwhile, wash the haddock fillets and pat dry. Brush the fillet lightly with olive oil. Season both sides with salt and black pepper. Place into a baking dish.

Preheat oven to 420°F.

Place on the middle rack of the oven and bake until fish flakes easily with a fork, about 15 minutes (when a fish is properly cooked, the flesh should flake off in pieces when you touch it with a fork).

Transfer to a serving plates and pour the sauce over them. Serve immediately.