I used a 9 x 9 inch baking dish.
Spoon about ½ cup of tomato sauce on to the bottom of the baking dish.
Layer 3 of the lasagna sheets on top - it doesn't matter if they overlap.
Spoon half of the vegetable mixture on top of the lasagne sheets and spread evenly to the edge of the dish.
Dollop another ½ cup of the tomato sauce on top and spread it out as best as you can.
Top with a quarter of the grated cheese (about ½ cup)
Layer three more of the lasagne sheets on top and spoon on the remaining vegetable mixture.
Carefully spread it over the lasagne sheets and then add another half cup of grated cheese.
Top this layer with the remaining lasagne sheets.
Spoon over the remaining tomato sauce and carefully spread it out to cover the lasagne sheets.
Sprinkle over the remaining grated cheese
Loosely cover the top of the lasagna with kitchen foil (making sure that it doesn't touch the top of the lasagna or the cheese will stick to it .... and you don't want that!)
Place on the middle shelf of the preheated oven and bake for 20 minutes.
Remove from the oven and take off the kitchen foil.
Return to the oven and cook for a further 10 minutes until the cheese has melted and started to bubble.
Leave to cool slightly before serving.