This casserole is prepared the night before and only needs a shove into the oven on the day of your feast!
2 tbsp olive oil
1 cooking onion, chopped
1 red sweet pepper, chopped
4 canned plum tomatoes, seeded and chopped
250 g white button mushrooms, sliced
freshly ground black pepper
3 1/2 cups milk
1/4 cup basil pesto
1/2 tsp salt
8 to 12 slices Italian, sourdough or challah bread
1 340-g pkg shredded Italian cheese blend, (mozzarella, asiago, provolone mix) or about 3 cups
1/4 cup grated Parmesan
Butter or oil a 13 x 9 x 2 in. (4 L) baking dish. Heat a large, non-stick frying pan at medium, add oil, onions and red pepper and cook, stirring 4 minutes; add tomatoes and mushrooms and cook, stirring, 5 minutes or until mushrooms are golden brown and have released their juices. Season with salt and pepper.
With a slotted spoon, arrange 1/3 of the onion mixture and 1 cup of the cheese on the bottom of the baking dish. Cover with a layer of bread (4 to 6 slices, depending on size, no overlapping). Repeat with onion-cheese layer, bread and final layer of onion-cheese.
In a large bowl, whisk together eggs, milk, pesto and salt. Pour into baking dish. Using a large spatula or plate, press down on top of casserole to totally submerge bread in liquid. (If floating persists, leave weights on overnight.) Cover and refrigerate 8 to 24 hours.
Remove from fridge 30 minutes before baking. Preheat oven to 400°F (200°C). Sprinkle the Parmesan cheese over the top and bake, uncovered, for 60 minutes or until set in the centre, puffy and golden brown. Let rest 5 to 10 minutes before serving.