Preheat oven to 220ºC. Spray 33x23 cm baking dish with non-stick cooking spray; set aside.
Melt the Stork Margarine in large saucepan, add leek and onion and cook until softened, but not coloured.
Stir in the flour and keep on gentle heat for 2-3 minutes stirring constantly. Pour in the milk, little by little stirring constantly and add one of the Knorr Vegetable Stock pot.
Reduce heat to low, then stir in red pepper and grated cheese. Stir until cheese is melted and leave on minimum heat, stirring occasionally.
Bring a large pan of water for the pasta to a rapid boil. Dissolve the second Knorr Vegetable Stock Pot into it (to season) the water. Add a little olive oil to stop the macaroni sticking. Add pasta, bring back to the boil then simmer until cooked. Drain and put the pasta water back into saucepan and return to heat, add mixed cut vegetables and blanch until partially soft then drain.
Stir the drained vegetables and macaroni into the cheese sauce and turn into the prepared baking dish.
Bake until golden brown, about 20 minutes.
BETTER FOR YOU TIPS : For increased fibre use wholewheat macaroni.