Prepare the vanilla custard according to package instructions or from scratch.
Cube the pound cake into bite-sized pieces.
Layer the ingredients in a large trifle dish or individual cups, starting with a layer of pound cake.
Add a layer of vanilla custard over the pound cake.
Sprinkle a layer of mixed berries on top of the custard.
Repeat the layering process until all ingredients are used, finishing with a layer of whipped cream.
Crush gingersnap cookies and sprinkle on top of the whipped cream.
Drizzle with maple syrup if desired and refrigerate for at least an hour before serving.