01 - Cube the sponge cake or ladyfingers and arrange half in the base of a large trifle dish. Sprinkle with orange juice or sherry if using for added moisture.
02 - Heat the milk until steaming in a saucepan. Whisk egg yolks with sugar and cornstarch in a separate bowl. Gradually pour hot milk into the yolk mixture while whisking constantly. Return everything to the pan and cook over medium heat, stirring continuously until thickened. Remove from heat, stir in vanilla, and let cool completely.
03 - Combine mixed berries with sugar and lemon juice in a bowl. Let stand for 10 minutes to allow the berries to release their natural juices.
04 - Beat the heavy cream, powdered sugar, and vanilla extract together until soft peaks form. Be careful not to overwhip.
05 - Layer half the custard over the cake base, then spoon in half the macerated berries. Add half the whipped cream. Repeat layers with remaining cake cubes, custard, berries, and whipped cream, ending with a layer of whipped cream on top.
06 - Decorate the top with chocolate eggs, colored sprinkles, and fresh mint leaves if desired. Refrigerate for at least 2 hours to allow flavors to meld before serving.