My mother-in-law throws this 3 ingredient masterpiece together before every picnic and gets asked for the recipe every single time. It is ridiculously easy but looks like it took hours.

Cover the dish tightly with plastic wrap or a lid to prevent freezer odors and ice crystals. Place the dish on a flat surface in the freezer and freeze for at least 4 hours, or until completely firm. For best texture and clean slices, freeze overnight.
When you are ready to serve, remove the dish from the freezer and let it sit at room temperature for about 10 minutes so it softens just slightly. Run a thin knife around the edges, then cut into squares. Use a small spatula to lift out portions, keeping the creamy, dotted surface intact.
Return any leftovers to the freezer promptly, covered well, and enjoy within 3–5 days for best flavor and texture.
Variations & Tips
For a slightly lighter version, use light lemon yogurt and light whipped topping; the texture will be a bit softer but still sliceable when well frozen. If you prefer more tart lemon flavor, stir in 1–2 teaspoons of finely grated lemon zest with the yogurt before folding in the whipped topping. For extra sweetness, sprinkle 1–2 tablespoons of powdered sugar over the yogurt before mixing, tasting as you go. You can also swap in vanilla or plain yogurt if lemon is too strong, or mix half lemon and half vanilla for a milder flavor that still pairs nicely with the blueberries. If fresh blueberries are very large, you can gently cut them in half so they distribute more evenly, but dry them well first so they don’t streak the mixture. For a layered look, spread half the lemon mixture into the dish, sprinkle over half the blueberries, then repeat with the rest and smooth the top. Food safety tips: Always start with clean, dry berries and discard any that are moldy or very soft; wash them under cool running water and pat completely dry before using so excess moisture doesn’t affect the texture. Keep the yogurt and whipped topping refrigerated until you are ready to mix, and do not leave the finished salad sitting at room temperature for more than 30 minutes; return it to the freezer promptly. If the salad has been left out long enough to become very soft and warm, it’s safer to discard the remainder rather than refreeze. Use the salad within several days for the best quality, and keep it tightly covered to prevent freezer burn and absorption of odors from other foods.