In a medium bowl, combine the mixed berries. Sprinkle with a teaspoon of honey or maple syrup and gently toss to coat. Set aside to macerate for about 10 minutes.
If preparing homemade custard, follow your favorite recipe and allow it to cool before using. If using store-bought, ensure it's at room temperature for easier layering.
In a large glass trifle bowl or individual serving cups, start by placing a layer of sponge cake cubes at the bottom.
Spoon a layer of vanilla custard over the cake layer, smoothing it out evenly.
Follow with a layer of the macerated berries, spreading them out to cover the custard.
Add a generous layer of whipped cream over the berries, smoothing it with the back of a spoon.
Repeat layers (cake, custard, berries, whipped cream) until you reach the top of your serving container, finishing with whipped cream. You can reserve a few berries for garnish.
Cover the trifle with plastic wrap and chill in the refrigerator for at least 1 hour, allowing the flavors to meld.
Just before serving, top with reserved berries and garnish with fresh mint leaves.
Notes
Chill for at least 1 hour before serving for best flavor.