For the pepper coulis, brush the peppers with the extra virgin olive oil and bake in a hot oven until browned. Remove from the oven and peel the skin whilst still hot. Discard seeds and whizz the remaining flesh in a food processor together with the balsamic vinegar and brown sugar. To prepare the filling, mix the hot vegetable stock together with the tomato paste and bring to the boil. Turn off heat, stir in couscous and cover for 5 minutes. When ready, fluff couscous with a fork. Stir in the tuna, pine nuts, raisins, parsley, garlic, basil and chopped eggs. Correct the seasoning with salt and pepper. Remove the outer leaves of the cabbage and discard. Carefully cut out the next 6-8 leaves (depending on the size of the cabbage) without breaking them. Blanch the leaves in salted water for 1 minute, drain and refresh under cold running water. Drain and dry with kitchen paper, then lay the leaves neatly onto a flat working surface. Divide mixture between the cabbage leaves and roll like ‘bragioli’. Place on a greased oven dish, drizzle with the extra virgin olive oil, sprinkle with the parmesan cheese and breadcrumbs and bake for 15 minutes just to brown. Serve the cabbage rolls with a side salad and a drizzle of pepper coulis.