Tuna, spinach & chargrilled vegetable calzone

Preheat the oven to 220ºC, gas mark 7 and put a baking tray in to heat up. Heat 1 tbsp oil in a large frying pan and add the onion with a pinch of salt. Fry for 5 minutes until softened. Remove to a plate. Fry the spinach in batches using the remaining 1 tbsp oil, then tip into a sieve. Cool a little, then squeeze out as much water as you can.

Dust the work surface and a rolling pin with flour, then roll 1 dough ball into a rough circle, about 25cm. Spread ½ the vegetable sauce over ½ the circle, leaving a 2cm border. Top with ½ the onion, the spinach, tuna and mozzarella and almost ½ the cheese (leave a little for sprinkling before baking). Repeat with the other ball of dough.

Brush the edges of the dough with a little water, then close each calzone and crimp with a fork, or your thumbs, to seal. Using a small sharp knife, make 3 slits in the top to allow the steam to escape.

Dust the preheated baking tray with flour. Add the calzones and sprinkle with the remaining cheese. Bake for 12-15 minutes until golden brown. Dress the rocket with the remaining ½ tbsp oil and a squeeze of lemon, then serve alongside.