Prepare the Crust:

• In a medium bowl, combine the shortbread crumbs, sugar, and melted butter. Stir until well combined.

• Press the mixture into the bottom of a 9-inch springform pan to form an even crust. Set aside.

Make the Fudge Layer:

• In a heatproof bowl, melt the white chocolate chips and butter together over a double boiler or in the microwave, stirring until smooth.

• Stir in the heavy cream and lemon zest until fully combined.

• Pour the fudge mixture over the prepared crust and smooth out evenly. Refrigerate while preparing the next layers.

Make the Lemon Curd:

• In a small saucepan, whisk together the lemon juice, lemon zest, sugar, and egg yolks.

• Cook over medium heat, stirring constantly, until the mixture thickens and coats the back of a spoon.

• Remove from heat and whisk in the butter until smooth.

• Let the lemon curd cool, then spread it over the fudge layer in the pan. Refrigerate while preparing the mousse layers.

Make the Lemon Mousse:

• In a small bowl, sprinkle the gelatin over the cold water and let sit for 5 minutes.

• In a large bowl, whip the heavy whipping cream and powdered sugar until stiff peaks form.

• Gently fold the gelatin mixture into the whipped cream along with the lemon curd.

• Spread the lemon mousse evenly over the lemon curd layer in the pan and refrigerate for 1 hour or until set.

Make the Blueberry Mousse:

• In a blender or food processor, puree the blueberries until smooth.

• In a small bowl, dissolve the powdered gelatin in a little water (about 1 tablespoon), then heat it until fully dissolved.

• Whip the heavy cream and powdered sugar until stiff peaks form.

• Gently fold in the blueberry puree and gelatin mixture.

• Spread the blueberry mousse over the lemon mousse and refrigerate for 2–3 hours, or until fully set.

Serve:

• Once set, remove the cake from the springform pan.

• Garnish with fresh blueberries before serving.