Combine sugar and eggs in a large bowl, stirring with a whisk.
Heat milk over medium-high heat until tiny bubbles form around edge (do not boil). Remove from heat, add cocoa and chocolate, stirring with a whisk until cocoa dissolves and chocolate melts. Gradually add hot milk mixture to sugar mixture, stirring constantly with a whisk. Stir in vanilla extract, cinnamon, and nutmeg. Add bread, tossing to coat. Let mixture stand for 30 minutes, tossing occasionally.
Spoon bread mixture into an 8-inch square baking dish coated with cooking spray and sprinkle with 2 tablespoons sugar. Bake 350 degrees for 40 minutes or until set. Serve with half and half. Serves 8.