01 -
Place blueberries and water in a medium saucepan over medium-high heat. Crush the berries with a potato masher or fork. Bring to a simmer, then lower temperature to medium-low and simmer for 2 minutes. Remove pan from heat and pour the mixture into a fine-mesh strainer over a glass measuring cup. Press on the berries to extract as much juice as possible, discarding the solids. Return juice to the pan, add sugar and lemon juice, and bring to a boil. Simmer for 2-3 minutes before removing from heat to chill completely in the refrigerator.
02 -
In a stand mixer with the whisk attachment, whip heavy cream to stiff peaks. Transfer whipped cream to a separate bowl. Replace the whisk with the paddle attachment and combine mascarpone cheese, sugar, vanilla extract, and almond extract until smooth and creamy. Gradually add blueberry syrup, 1/4 cup at a time, mixing thoroughly after each addition. Incorporate 1 cup of whipped cream and mix until combined. Gently fold in the remaining whipped cream.
03 -
Dip each ladyfinger into the blueberry syrup until soaked but not soggy, then arrange an even layer along the bottom of an 8-inch square dish. Spread half of the mascarpone filling over the ladyfingers. Add a second layer of blueberry syrup-soaked ladyfingers on top of the filling, then spread half of the remaining filling over this layer. Transfer the remaining filling to a pastry bag with a large round tip (or a ziplock bag with the corner cut off) and pipe the filling evenly as the top layer. Cover and refrigerate for at least 6 hours or overnight. Serve slices with additional blueberry syrup drizzled on top.