Pour the yogurt onto the prepared baking sheet and use a spatula or knife to spread it into a thin layer.
Place the peanut butter in a large microwave-safe bowl and microwave for 30 to 60 seconds or until pourable. Drizzle the warm peanut butter over the yogurt.
Use a toothpick or a butter knife to swirl the peanut butter into the yogurt. Sprinkle with berries and place in the freezer to set for at least 1 hour.
Once solid, break the bark into 8 pieces. Store in a freezer-safe bag for up to 1 month.