01 - Using an electric mixer or whisk, beat the cold heavy whipping cream in a chilled mixing bowl until soft peaks form. Add the powdered sugar and vanilla extract, then continue whipping until stiff peaks form. Set aside in the refrigerator until ready to assemble.
02 - If using the optional sugar, place the fresh blueberries in a bowl and toss with 1 tablespoon granulated sugar. Let sit for 10 minutes to macerate, which will draw out some juices and enhance the natural sweetness. Skip this step if you prefer a tart contrast.
03 - Arrange half of the cubed pound cake or angel food cake in an even layer at the bottom of a trifle dish or large glass bowl. Press gently to create a stable base for the layers.
04 - Spoon half of the lemon curd over the cake cubes, using the back of a spoon to spread it into an even layer. Ensure the curd covers most of the cake surface for optimal flavor distribution.
05 - Scatter half of the prepared blueberries over the lemon curd layer, distributing them evenly for visual appeal and consistent fruit flavor in each serving.
06 - Spread half of the whipped cream over the blueberries, creating an even layer that seals in the fruit. Use a spatula to smooth the top for a clean presentation.
07 - Repeat the layering process with the remaining ingredients: cake cubes, lemon curd, blueberries, and whipped cream. End with the whipped cream on top for a finished appearance.
08 - Sprinkle the fresh lemon zest over the top of the trifle and add a few extra blueberries as a garnish. Cover and refrigerate for at least 1 hour before serving to allow the flavors to meld and the cake to soften slightly. The trifle can be made up to 1 day in advance.