Line a baking sheet with parchment paper.
Aim for a rimmed sheet so nothing spills. Set aside. Clear space in your freezer for the tray.
In a mixing bowl, whisk together the Greek yogurt, keto sweetener, vanilla extract, and a small pinch of sea salt.
Taste and adjust sweetness to your liking. Remember, flavors dull slightly when frozen.
Spread the yogurt mixture onto the parchment-lined sheet in an even layer, about 1/4 inch thick. Use a spatula to smooth the surface.
Scatter the sliced strawberries evenly over the top.
Press them gently into the yogurt so they adhere.
Add any optional toppings you like—chopped nuts for crunch, shredded coconut for texture, or a light sprinkle of chia seeds for fiber. Keep toppings fairly small so the bark breaks cleanly later.
If using chocolate, either sprinkle sugar-free chips now or melt sugar-free dark chocolate and drizzle thin zigzags over the surface.
Place the tray flat in the freezer and freeze for 2–4 hours, or until completely firm.
Once frozen, lift the bark by the parchment and place it on a cutting board. Break it into pieces by hand or use a sharp knife for cleaner squares.
Transfer pieces to a freezer-safe container or bag.
Keep frozen until ready to eat.