In a medium saucepan over medium heat, combine blueberries and water. Stir, mashing the berries until bubbling, about 8–10 minutes. Remove, strain, and cool.

In a mixing bowl, pour heavy cream and add sugar. Whip until stiff peaks form, about 3–5 minutes. Set aside.

In another bowl, mix mascarpone and vanilla until smooth. Gently fold in whipped cream until no streaks remain.

Slowly drizzle cooled blueberry syrup into mascarpone mixture and stir gently until mixed well.

Prepare espresso mixture in a shallow dish. Quickly dip each ladyfinger into the mix and layer at the bottom of a dish.

Spread half of the blueberry cream mixture over the soaked ladyfingers, ensuring even distribution.

Repeat with remaining ladyfingers and cream, smoothing out the last layer evenly.

Cover the dish tightly and chill in the refrigerator for at least 6 hours or preferably overnight.

In a small saucepan, whisk together blueberry jam, cornstarch, water, and egg. Stir until thickened, about 5–7 minutes. Cool before spreading on tiramisu.

Garnish with fresh blueberries and mint before serving for added color.