Preheat oven to 190ºC/fan 170ºC/gas mark 5. Place onion, garlic, peppers, courgettes, mushrooms, tomatoes, and stock in a non-stick saucepan and stir to mix. Cover and cook over a medium heat for 10-15 minutes or until vegetables are beginning to soften, stirring occasionally.

Meanwhile, make cheese sauce. In a small bowl, mix cornflour with a little of the milk until smooth. Pour remaining milk into a non-stick saucepan; stir in cornflour mixture. Bring to the boil over medium heat, stirring continuously, until thickened and smooth. Simmer for 2 minutes, stirring. Remove pan from heat; stir in 75g of the cheese and black pepper to taste.

Stir dried herbs into vegetable mixture; season with black pepper.

Assemble lasagne. Spoon half of the vegetable mixture over the base of a shallow ovenproof dish or roasting tin; cover this with half of the lasagne sheets (in a single layer). Spoon over a little of the cheese sauce (just enough to thinly cover pasta). Repeat the layers of vegetable mixture and lasagne; pour over remaining cheese sauce to cover lasagne completely. Sprinkle remaining cheese over top.

Bake in oven for about 40 minutes or until browned on top and bubbling. Serve with a mixed leaf salad.