Cut the bread into 1-inch cubes. There should be 7-8 cups of bread..
Soak the bread and raisins with the milk. It may not absorb all of the milk, but it should be saturated.
In small bowl melt 2 Tablespoons of butter in the microwave.
Whisk melted butter, vanilla, eggs, sugar, and spices in a medium bowl. Pour the egg mixture over the bread. Stir to incorporate. Allow to sit for 20 minutes while the oven preheats. If you would like it to be softer and more custardy, you can allow it to sit for longer.
Preheat your oven to 350 degrees.
Melt remaining 2 Tablespoons of butter in the microwave. Pour melted butter into a 9x13 baking dish and swirl butter to coat the bottom and sides.
Transfer the bread and egg mixture to the pan. Place in preheated oven.
Bake for 30-45 minutes or until the custard is set and the top is brown, and it pulls slightly away from the sides.
Cut into slices and serve immediately with maple syrup if desired.