“S’more, Please” Trifle

Ingredients (9)

• 1 package chocolate cake mix (regular size)
• 1 can (12 ounces) diet lemon-lime soda
• 2-1/2 cups plus 2 tablespoons fat-free milk, divided
• 2 packages (1.4 ounces each) sugar-free instant chocolate pudding mix
• 1 carton (8 ounces) frozen fat-free whipped topping, thawed
• 1/2 cup dark chocolate chips
• 10 whole reduced-fat graham crackers, divided
• 1 jar (7 ounces) marshmallow creme
• Grated chocolate, optional