Halve the tomatoes lengthways and place on a baking tray. Season well and splash over some balsamic vinegar and oil. Roast at 120°C for 1-1 1/2 hours until softened and slightly dehydrated.

For the piadine, sift the flour, baking powder and salt into the bowl of a mixer with the dough hook attached. Add the lard and mix on a low speed. Gradually add about 200ml lukewarm water until a smooth dough forms. It should feel soft, silky and pliable: if it's too wet, it will be difficult to handle; if it's too dry, it will crack easily. Form into 8 balls and leave to rest for 30 minutes on a floured surface, covered with a damp towel.

For the best results, roll the piadine to order and cook in a cast-iron pan. You could also try doing them on the barbecue or in a good-quality non-stick pan; the trick is to get it super-hot.

When the pan is very hot, add the dough disc (about 2mm thick), having first shaken off any excess flour. It will start to bubble and lift off the pan. Rotate the dough for even cooking until it has brown spots across the base, then flip the piadina and turn the heat down.

Spread over some njuda, stracchino and a couple of the roasted tomato halves. Fold the disc over and continue to cook on each side until the filling is melted and warm.

Serve immediately with fresh rocket leaves and lemon wedges.

After cooking a few piadine, a residue of browned flour will build up on the pan which will need to be wiped off before cooking more.

(Note: stracchino may need to be ordered in advance from an Italian delicatessen or cheese shop.)

Serves 4