01 - Line an 8x8-inch baking pan with parchment paper, leaving an overhang on opposite sides for easy removal later.
02 - Combine granola, honey or maple syrup, and melted coconut oil in a medium bowl. Mix until all ingredients are evenly coated.
03 - Transfer the granola mixture to the prepared pan. Press firmly and evenly into the bottom using the back of a spoon or spatula to create a compact layer.
04 - In a separate bowl, whisk together Greek yogurt, honey or agave syrup, and vanilla extract until completely smooth and well combined.
05 - Spread the yogurt mixture evenly over the granola base, using a spatula to create a smooth, level surface.
06 - Distribute the mixed berries evenly over the yogurt layer. Sprinkle chia seeds across the top if using for added texture and nutritional benefits.
07 - Place the pan in the freezer for at least 4 hours, or until completely firm and set throughout.
08 - Using the parchment paper overhang, lift the frozen slab out of the pan. Transfer to a cutting board and let sit at room temperature for 5-10 minutes to soften slightly for easier slicing.
09 - Cut into 12 even bars using a sharp knife. Store in an airtight container in the freezer. Serve frozen or allow to thaw for a few minutes before eating.