8x 125g skinless haddock loin fillets from your local Fisherman’s Market
600g of potatoes, quartered
454g can of sweetcorn in water
500g bag of ready-washed spinach
4 leeks, thickly sliced
500ml skimmed milk, plus 5 tbsp
30g unsalted butter
30g plain flour
1 tsp English mustard
75g mature reduced-fat cheese, grated
Heat oven to 200C. Boil the potatoes for 15-20 mins until tender, then drain. Reserve 6 tbsp of the sweetcorn and blitz the rest (with its juice) using a hand blender or a food processor until completely smooth, then mash into the potatoes. Cook the spinach following pack instructions – if you have a microwave, choose this method.
Put the leeks in a pan with the 500ml milk and the butter. Cook gently, part-covered, for 8 mins until the leeks are tender. (Keep an eye on things as milk can easily boil over.) Mix the 5 tbsp milk with the flour and mustard, then stir into the leek mixture – keep stirring until thickened. Take off the heat and stir in three-quarters of the cheese.
Squeeze as much liquid as you can from the spinach, then arrange on the base of 2 gratin dishes. Place 2 haddock loins on top of each, then spoon over the leek & cheese sauce. Top with the sweetcorn mash. Mix the remaining corn and cheese, and scatter on top. Place the dishes on a baking tray and cook for 18-20 mins until the fish flakes when tested and the top is golden.