Line a rimmed baking sheet with parchment paper. Make sure the parchment covers the bottom fully and comes up the sides slightly so the yogurt does not run underneath.

In a medium bowl, stir together the Greek yogurt, 2 tablespoons of honey, and vanilla extract until smooth and combined. Taste it. It should be mildly sweet. If your kids prefer sweeter, add another teaspoon of honey now.

Pour the yogurt mixture onto the parchment-lined pan. Use an offset spatula or the back of a large spoon to spread it into an even rectangle about 1/4 inch thick. Try to keep the thickness consistent so it freezes evenly all the way across.

Scatter the sliced strawberries, blueberries, and raspberries evenly over the yogurt surface. Press each piece of fruit gently so it nestles into the yogurt slightly rather than sitting loose on top. Sprinkle granola over the berries if using, then drizzle a thin stream of honey across the whole surface.

Slide the pan into the freezer and freeze for at least 2 hours, or until the bark is completely firm all the way through. Check the center by pressing with your finger. It should feel hard with no give. If it still feels soft in the middle, give it another 30 minutes.

Lift the parchment off the pan and set the bark on a cutting board. Break it into irregular pieces with your hands, similar to how you would break a chocolate bar. Pieces will vary in size and that is fine. Transfer to a zip-top freezer bag or airtight container, layering pieces with parchment so they do not freeze together into a solid block.