Prepare the Pan: Line a quarter sheet pan (approx. 9x13-inch / 23x33-cm) with parchment paper, smoothing it out to cover the bottom and corners to prevent sticking.
Toast the Almonds: Place the sliced almonds in a small, dry skillet over medium-low heat. Toast for 2–4 minutes, stirring frequently, until they are fragrant and lightly golden. Remove immediately to a small plate to cool.
Create the Yogurt Base: In a large mixing bowl, whisk together the non-fat Greek yogurt, maple syrup, vanilla extract, and almond extract. Zest the entire lemon directly into the bowl.
Infuse with Citrus: Cut the zested lemon in half and squeeze 3 tablespoons of fresh juice into the yogurt mixture. Stir well with a spatula until smooth and fully combined.
Assemble the Bark: Pour the yogurt mixture onto the prepared baking sheet. Spread it into an even layer, approximately ¼-inch thick. Evenly scatter the fresh raspberries and toasted almonds over the top.
Freeze: Place the pan on a flat surface in the freezer. Freeze for at least 4 hours, or until the bark is completely solid.
Serve: Lift the parchment paper to remove the bark from the pan. Break it by hand into rustic shards or cut with a sharp knife. Allow the pieces to sit at room temperature for 5–10 minutes before eating to soften slightly for the best texture.