Trim and thinly slice the celery, the courgettes and the spring onions. Peel and thinly slice the carrots. Thinly slice the mushrooms. Halve and de-seed the pepper, top and tail the mangetout and chop them into thin strips. Place the sweetcorn in a sieve over a small bowl and soak the bean sprouts in cold water for 5 minutes before rinsing thoroughly.

Heat 2 tablespoons of the oil over a high heat in a large frying pan or wok, and add the cashew nuts.

Cook them briefly, stirring continually, until golden. Keeping the oil in the pan, remove the cashew nuts and put them to one side.

Add the celery and carrots to the wok and stir-fry for 2 minutes over a high heat. Add the remaining vegetables one batch at a time, stirring well between each addition, and stir-frying for a total of 4 minutes.

Combine the ground ginger, arrowroot powder, soy sauce, tomato puree, vinegar and sugar, and mix well. Add this mixture to the pan and cook for 2 minutes, stirring well, until thickened. Transfer the mixture to a bowl and leave to cool.

Lay 2 sheets of the filo pastry, slightly overlapping, on a clean work surface. Lay the next 2 sheets on top with the pastry seam lying in the opposite direction. Repeat the process with the next 2 sheets in the original direction and the last 2 in the opposite direction. You should have a square of pastry with sides measuring about 18 in (460 mm) long.

Carefully spread all the vegetable mixture over the pastry, leaving a 1 in (25 mm) space around the edges. Fold in 2 sides of the pastry, then carefully roll up the strudel. Transfer to a lightly oiled baking tray. Brush the strudel with the remaining oil and sprinkle with the sesame seeds. Bake in the Oven for about 30 minutes until golden-brown. Allow to cool for 5 minutes, then cut into thick slices and serve.