01 - Line an 8x8-inch baking pan with parchment paper, leaving an overhang on sides for easy removal later.
02 - In a medium bowl, combine granola, honey (or maple syrup), and melted coconut oil. Mix until evenly coated and well combined.
03 - Transfer the granola mixture to the prepared pan. Press firmly and evenly across the bottom using the back of a spoon or spatula to create a compact base layer.
04 - In a separate bowl, whisk together Greek yogurt, honey (or agave syrup), and vanilla extract until completely smooth and well incorporated.
05 - Pour the yogurt mixture over the granola base. Spread evenly with a spatula to create a uniform layer.
06 - Distribute mixed berries evenly over the yogurt layer. Sprinkle with chia seeds if using for added texture and nutritional benefits.
07 - Transfer the pan to the freezer. Freeze for at least 4 hours or overnight until completely set and firm to the touch.
08 - Using the parchment overhang, lift the frozen slab from the pan. Place on a cutting board and let sit for 5-10 minutes to soften slightly. Cut into 12 even bars using a sharp knife.
09 - Store bars in an airtight container in the freezer. Serve frozen or allow to thaw for 2-3 minutes before eating for a softer texture.