Arrange the doughnuts and bread in the bottom of a lightly greased 2-quart baking dish.
Beat the milk, cream and eggs in a large bowl until well blended. Add the sugar, orange zest, cinnamon and vanilla. Whisk until homogenous.
Pour the liquid mixture over the bread cubes in the baking dish and let stand until the liquid is absorbed, about 1 hour. (You can freeze the casserole at this stage for up to 1 month. Defrost in the refrigerator overnight before baking, or cook directly from the freezer in a 325-degree oven, covered with aluminum foil, for 65 to 75 minutes.)
Preheat the oven to 375 degrees F. Bake until the center is just set, 50 to 55 minutes. Cool slightly before serving. Top with maple syrup and fresh berries.