Prepare the Pan: Line a quarter sheet pan with parchment paper, ensuring it covers the bottom and sides to prevent sticking.

Whisk the Yogurt Base: In a large mixing bowl, combine the non-fat Greek yogurt, maple syrup, vanilla extract, and ground cinnamon. Stir with a spatula until the mixture is smooth and uniform.

Spread the Mixture: Pour the yogurt mixture onto the prepared sheet pan. Use the spatula to spread it into an even layer, approximately ¼ to ½ inch thick.

Create the Peanut Butter Swirl: Place the natural unsalted peanut butter in a small microwave-safe bowl. Heat for 10–15 seconds, just until it becomes pourable. Drizzle the warmed peanut butter over the yogurt base, then use the tip of a knife to gently create decorative swirls.

Scatter the Toppings: Evenly sprinkle the dark chocolate mini chips, miniature marshmallows, and whole-wheat graham cracker crumbs across the entire surface.

Freeze Until Solid: Carefully transfer the sheet pan to a level spot in your freezer. Let it freeze for at least 3 hours, or until the bark is completely firm to the touch.

Portion and Serve: Lift the parchment paper to remove the bark from the pan. Place it on a cutting board and break it into 12 irregular pieces. Serve immediately.