24-Hour Omelet with Sun-Dried Tomatoes and Mozzarella
3 tablespoons unsalted butter, softened, plus extra for greasing the dish
10 slices high-quality white sandwich bread
3 cups shredded mozzarella cheese
1/2 cup grated Parmesan cheese
1/2 cup oil-packed sun-dried tomatoes, drained, patted dry, and chopped coarse
8 large eggs
3 cups whole milk
1 onion, grated
1 teaspoon table salt
1 teaspoon ground black pepper
1 teaspoon dry mustard
1/2 teaspoon Tabasco sauce
Grease bottom and sides of 9 by 13-inch baking dish (or casserole dish of similar size) with butter. Spread remaining 3 tablespoons butter over 1 side of each slice of bread, then cut bread into 1-inch pieces. Scatter half of bread evenly into prepared dish and sprinkle with half of mozzarella, Parmesan, and tomatoes. Repeat with remaining bread, mozzarella, Parmesan, and tomatoes. Whisk together eggs, milk, onion, salt, pepper, mustard, and Tabasco and pour evenly over bread. Press lightly on the bread to submerge. Cover tightly with plastic wrap and refrigerate for at least 8 hours.
Adjust oven rack to middle position and heat oven to 350 degrees. Remove dish from refrigerator and uncover. Bake until puffed and golden brown, about 1 hour. Serve immediately.
To Make Ahead
The omelet can be made and held in the refrigerator, wrapped tightly with plastic wrap, for up to 36 hours before baking.
This dish can be made up to 36 hours ahead of time, making it a good choice for brunch on a busy weekend. We prefer the flavor and texture of Pepperidge Farm Hearty White Bread, although any firm white sandwich bread will do. Serves 6 to 8