1. Heat a little oil in a pan and add the sliced onion, cook stirring frequently until the onion starts to cook and soften, add the chopped garlic, continue to cook the onions, add a knob of butter and cook until the onions are caramelised and turn golden brown (be careful not to burn them)
2. Take the haddock and spread the tomato paste on the inside of the haddock fillets, fold the haddock fillets in half with the tomato side on the inside. Place on a baking tray, brush the fish with oil and place under a preheated grill. Cook until the fish is just cooked.
3. Remove the fish from the grill and top with the caramelised onions, sprinkle with grated cheese and place back under the grill until the cheese melts.
4. In a pot, wilt the spinach in a little butter, season with salt, pepper and a pinch of nutmeg.
5. Spoon a little spinach on to the plates and top with the fish.
