✅ Step 1: Make the Blueberry Syrup

1. Add blueberries, sugar, lemon juice, water, and vanilla to a medium saucepan.
2. Place the pan over medium heat and bring the mixture to a gentle simmer.
3. Stir occasionally, using a wooden spoon to mash some of the berries as they cook.
4. After 10–12 minutes, the mixture should thicken slightly, and the berries will burst.
5. Turn off the heat and strain the syrup through a fine mesh strainer into a clean bowl, pressing gently with a spoon to extract all the liquid.
6. Let the syrup cool to room temperature. It should be slightly thick but still fluid.

✅ Step 2: Prepare the Mascarpone Cream

1. Pour cold heavy cream into a large mixing bowl and beat with a hand mixer on medium-high speed until soft peaks form (about 2–3 minutes).
2. In a separate bowl, combine mascarpone cheese, powdered sugar, vanilla extract, and lemon zest.
3. Use a spatula or low-speed mixer to blend until smooth and creamy.
4. Gently fold the whipped cream into the mascarpone mixture in batches. Mix slowly using a folding motion to keep the texture light and airy.

Pro Tip: Do not overmix or whip after combining—you want a soft, cloud-like texture.

✅ Step 3: Assemble the Tiramisu

1. Pour the cooled blueberry syrup into a shallow bowl.
2. One at a time, quickly dip each ladyfinger into the syrup—just 1–2 seconds per side. Do not oversoak.
3. Arrange a layer of dipped ladyfingers on the bottom of a 9x9" dish.
4. Spoon half of the mascarpone cream over the ladyfingers. Spread evenly with an offset spatula.
5. Repeat with another layer of syrup-dipped ladyfingers.
6. Add the remaining mascarpone cream and smooth the top with the spatula.

Mistake to Avoid: Oversoaking the ladyfingers can make the dessert soggy. A quick dip is enough to absorb the syrup without breaking apart.

✅ Step 4: Chill and Decorate

1. Cover the dish with plastic wrap or a lid.
2. Chill in the refrigerator for at least 4 hours, preferably overnight, to allow the layers to set and flavors to meld.
3. Just before serving, top with fresh blueberries, lemon zest, and optional mint leaves or powdered sugar.
4. Slice with a clean, sharp knife and serve chilled.