01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish with melted butter.
02 - In a large mixing bowl, whisk together eggs, milk, Dijon mustard, salt, and pepper until thoroughly combined.
03 - Layer half of the bread cubes evenly in the prepared baking dish.
04 - Sprinkle half of the ham, turkey, and Swiss cheese over the bread. Dot with half of the cream cheese cubes.
05 - Drizzle half of the raspberry preserves over the layer. Repeat with remaining bread, meats, Swiss cheese, cream cheese, and preserves.
06 - Pour the egg mixture evenly over the casserole, pressing gently to soak the bread. Cover with foil and refrigerate for at least 1 hour, or overnight for best flavor.
07 - Remove from refrigerator while oven preheats. Bake covered for 30 minutes, then uncover and bake for an additional 15 minutes or until golden and set.
08 - Cool for 10 minutes. Dust with powdered sugar and serve warm, with extra raspberry preserves on the side.