Smoked haddock and watercress tart

Method

1. Put a baking sheet in the oven and preheat to 180°C/fan160°C/gas 4. Heat a splash of oil in a pan and soften the onion for 5 minutes, then remove from the heat. Mix the eggs with the milk and most of the grated Parmesan. Fold in the watercress and season well with black pepper.
2. Remove the skin from one of the smoked haddock fillets and chop into chunks (reserve the other fillet for eating the next day).
3. Spread the softened onion over the base of the tart, then pour over the egg mixture, scatter over the haddock pieces and sprinkle with the remaining Parmesan. Bake on the preheated sheet for 18-20 minutes until the filling is just set and the pastry is golden. Serve warm, in slices, with the vinaigrette alongside for drizzling if you wish.