Vegetarian sausage rolls

Preheat the oven to 200 degrees C, gas mark 6, and line a large baking tray with baking parchment. Pierce the sweet potato all over with a fork and bake for 40 minutes until tender. Put the nuts in a roasting tin and add to the oven for the final 10 minutes. Set both aside to cool for 10 minutes.

Meanwhile, heat the oil in a non-stick frying pan and gently fry the onion for 8-10 minutes until soft. Add the wine (or port) and fry for 2-3 minutes until the liquid has bubbled off. Tip into a mixing bowl with the thyme, mustard and cheddar. Scoop out the potato flesh and add to the bowl (discard the skin). Roughly grind the nuts in a food processor and add to the bowl. Season and mix together with ½ the beaten egg.

Unroll the pastry and cut into thirds (to make 3 strips about 11cm x 23cm). Roll a third of the filling into a sausage and put in the middle of a strip. Brush one edge of the pastry with egg, then roll the pastry over from the other side to enclose the filling. Brush with egg and sprinkle with a third of the nigella seeds.

Repeat with the remaining pastry, filling, egg and seeds. Cut each roll into 6 pieces and put on the lined baking tray. Bake for 20-25 minutes until golden. Cool for 10 minutes then serve.