01 - Whip heavy cream with powdered sugar and vanilla extract in a mixing bowl until stiff peaks form. Refrigerate until ready to assemble.
02 - Toss fresh blueberries with granulated sugar if using. Let stand for 10 minutes to release juices.
03 - Arrange half of the cake cubes in an even layer across the bottom of a trifle dish or large glass bowl.
04 - Spread half of the lemon curd evenly over the cake layer using a spatula.
05 - Distribute half of the blueberries over the lemon curd layer.
06 - Spread half of the whipped cream over the blueberries in an even layer.
07 - Layer remaining cake cubes, lemon curd, blueberries, and whipped cream in the same order.
08 - Sprinkle lemon zest over the top and scatter a few extra blueberries for visual appeal.
09 - Refrigerate for at least 1 hour to allow flavors to meld and layers to set before serving.