Spray an 8"x11" casserole with cooking spray.
Toast bread until golden brown on both sides.
Arrange brioche in casserole. Set aside.
In a large bowl, whisk together milk, cream, eggs, vanilla, brown sugar, gingerbread spice, salt, and molasses.
Pour over brioche.
Press bread down to ensure even coating.
Sprinkle with chocolate chips.
Cover casserole with plastic wrap.
Refrigerate overnight.
Remove casserole from refrigerator 30 minutes prior to baking.
Heat oven to 350 degrees F.
Remove plastic wrap.
Bake casserole until puffy and set, about 25-30 minutes.
Serve immediately.