Vegetable lasagne

Name: Vegetable lasagne
Cuisine: European, Italian, Mediterranean
Ingredients: 110g mushrooms, quartered; 2 large onions, chopped; 150ml passata; 110g courgettes, sliced; 110g aubergines, sliced; ½ red pepper, deseeded and sliced; ½ yellow pepper, deseeded and sliced; 110g baby sweetcorn; 2 x 400g cans chopped tomatoes; ½ level tsp sweetener; 12 dried lasagne sheets; 500g fat-free natural fromage frais; 25g reduced-fat Cheddar cheese, grated