Preheat the oven to 220°C.
Toss peppers, courgettes, aubergines, and tomatoes with oil, oregano, chilli, and seasoning then roast for 25 minutes.
Slowly fry onions until soft, then add sugar and cook until caramelised.
Mix oil, 175ml lukewarm water, and vinegar in a bowl.
Combine flour, salt, egg, and the water mixture to form a soft dough.
Knead the dough for 15 minutes, then rest in an oiled bowl for 30 minutes.
Toss roasted vegetables with lemon juice, zest, and fresh herbs.
Mix couscous and bouillon with 150ml boiling water and soak for five minutes.
Fluff couscous with oil and seasoning, then combine with roasted vegetables.
Roll and stretch the dough on a floured tablecloth until paper thin.
Brush the pastry with melted salted butter.
Layer the filling, half the cheese, couscous, and remaining cheese over one third of the pastry.
Roll the strudel using the tablecloth and seal the edges.
Place the strudel on a tray in an 'S' shape and brush with unsalted butter.
Bake at 220°C for 10 minutes, then reduce to 200°C for 50 minutes, brushing with butter every 10 minutes.