50 g (2 oz) butter, melted, plus extra for greasing
250 g (8 oz) frozen leaf spinach, defrosted
4 tablespoons double cream
150 g (5 oz) cream cheese
2 tablespoons chopped dill or chives
250 g (8 oz) salmon fillet, cut into 1-cm (1/2-inch) cubes
4 filo pastry sheets, approximately 45 x 25 cm (18 x 10 inches)
hollandaise sauce, to serve (optional)
salt and pepper
Preheat the oven to 200°C (400°F), Gas Mark 6, and lightly grease a baking sheet. Place the spinach in the middle of a clean tea towel, bring up the edges and twist the spinach in the tea towel over a sink to squeeze out the excess moisture. Chop roughly, then place in a bowl with the double cream, cream cheese, herbs and seasoning. Mix well to combine, then gently fold in the diced salmon. Set aside.
Brush both sides of the filo pastry sheets with the melted butter, then cut in half widthways to create 8 pieces, approximately 23 x 25 cm (9 x 10 inches). Place one half of each sheet over the other to form 4 crosses.
Spoon the salmon mixture into the centre of each pastry cross and scrunch up the edges of the pastry towards the filling, without completely covering it, to make 4 tarts.
Transfer the tarts to the baking sheet and cook in the preheated oven for 12–15 minutes, until the pastry is golden and the fish is just cooked. Remove and serve with a drizzle of warmed hollandaise sauce, if desired.