Line your pan. Use a rimmed baking sheet or 9x13-inch pan.
Line it with parchment paper so the bark releases cleanly after freezing.
Mix the yogurt base. In a bowl, whisk Greek yogurt, sweetener, vanilla, and salt. If using protein powder, whisk it in until smooth. The mixture should be slightly sweet with a creamy, spreadable texture.
Adjust sweetness. Taste and tweak.
Add a touch more sweetener if needed. Remember that cold dulls sweetness, so the mixture should taste a hair sweeter than you want the final bark.
Spread it out. Pour the yogurt onto the lined pan. Use a spatula to spread it into an even layer about 1/4-inch thick.
Thinner freezes faster and breaks more easily.
Add toppings. Scatter berries, nuts or seeds, coconut, and chocolate evenly. Press gently so they stick. Keep toppings light to avoid icy patches.
Freeze until firm. Place the pan flat in the freezer for 2–4 hours, or until completely solid.
Overnight is fine.
Break into pieces. Lift the parchment onto a cutting board. Use your hands to break the bark into shards. For cleaner lines, use a chef’s knife to cut it into squares.
Store properly. Transfer pieces to a freezer-safe container or zip-top bag with parchment between layers.
Freeze until ready to eat.
Serve smart. Let a piece sit at room temperature for 2–3 minutes before eating for the best creamy texture.