1. Place the butter and sliced onion in a microwave casserole dish and cook on High for 5 minutes or until soft. Remove half the onion, spreading the remainder over the base of the dish.
2. Sprinkle with a little basil, cover with half of the tomatoes, sugar, salt and pepper. Repeat the layers.
3. Sprinkle over the breadcrumbs and dot witht the butter. Cook on High for 5 minutes.
You may brown under a preheated grill; based on a 600W oven