In a medium bowl, mix agave and yogurt.

Line a 9-inch by 13-inch baking dish with parchment paper. Use a spatula or knife to spread the yogurt as thin as possible over the entire bottom of the dish.

Add the nuts over the top of the yogurt. Use your fingers to slightly press them into the yogurt.

Layer on the berries, slightly pressing into the yogurt.

Cover with plastic wrap or foil and place in the freezer overnight.

Break bark apart into pieces when ready to serve.