Spinach and smoked trout roulades

Method

1. Heat the oven to 140°C fan/gas 3. Put a large, deep frying pan over a high heat, then add the spinach. Toss the leaves with tongs for a few minutes until they have completely wilted, then transfer to a sieve to cool. Once cool enough to handle, squeeze out as much liquid as you can (one small handful at a time), then put in a blender with the egg yolks, flour and a pinch of salt. Whizz until smooth, then transfer to a bowl.
2. Use an electric whisk to whisk the egg whites in a separate clean bowl until stiff then, a third at a time, fold the whites into the spinach mixture, taking care not to beat out too much of the air. Line the tray with baking paper, then pour the mixture into it, smoothing into a neat rectangular shape with a spatula or palette knife – it should be around 1cm thick. Bake for 10 minutes, then leave to cool.
3. While the sponge bakes, prepare the filling. Put the cream cheese in a bowl and stir in the trout (or salmon), pink peppercorns, chives and half the lemon zest. Season to taste with salt and some of the lemon juice.
4. Once cooled, tip the sponge out onto a board, peel off the paper, then turn the sponge back over, so that the smooth side is touching the board. Spread the salmon filling evenly over the sponge, then roll it up tightly along the longest edge so you are left with a long, slim roll (see Make Ahead).
5. Use a serrated knife to cut the roulade into 1cm slices. Serve with a little more lemon zest sprinkled over.