Prepare the Pan: Line your quarter sheet pan with a sheet of parchment paper, ensuring it lies flat against the bottom and corners. This prevents sticking and makes cleanup a breeze.
Toast the Almonds: Place the sliced almonds in a small, dry skillet over medium-low heat. Toast for 2-4 minutes, tossing frequently, until they are fragrant and lightly golden. Immediately remove them from the pan to a small plate to cool completely.
Create the Yogurt Base: In a large mixing bowl, combine the Greek yogurt, maple syrup, vanilla extract, and almond extract. Zest the entire lemon directly into the bowl.
Infuse with Citrus: Halve the zested lemon and squeeze 3 tablespoons of fresh juice into the yogurt mixture. Stir with the spatula until everything is smoothly and evenly incorporated.
Assemble the Bark: Pour the yogurt mixture onto the prepared sheet pan. Use the spatula to spread it into an even layer, roughly ¼-inch (about ½ cm) thick. Artfully scatter the fresh raspberries and toasted almonds over the entire surface.
Freeze Until Firm: Carefully transfer the pan to a level spot in your freezer. Freeze for at least 4 hours, or until the bark is completely solid and snaps when pressure is applied.
Shard and Serve: Lift the parchment paper to remove the frozen bark from the pan. Break it by hand into large, rustic pieces or use a sharp knife to cut it into more uniform squares. For the best texture, let the shards sit at room temperature for 5-10 minutes before enjoying.