Make the blueberry compote

• Combine the blueberries with the granulated sugar and a squeeze of lemon juice in a saucepan.
• Cook over medium heat until the berries soften and release their juices, then let cool completely.

Whip the lemon mascarpone cream

• Beat the mascarpone with the powdered sugar and lemon zest until smooth.
• Whip the cold heavy cream to soft peaks and fold it into the mascarpone mixture with a little lemon juice.

Assemble the tiramisu

• Dip the ladyfingers briefly in lemon juice diluted with water and line the bottom of the dish.
• Spread half of the mascarpone cream, then the blueberry compote and dollops of lemon curd.
• Repeat with a second layer of ladyfingers and the remaining cream.

Chill and serve

• Cover and refrigerate until set.
• Top with fresh blueberries and lemon zest before serving.