Preparing your Simple Berry Trifle can be accomplished by following these straightforward steps:

1. Prepare the Berries: Rinse the mixed berries under cold water. If using strawberries, slice them into quarters.
2. Sweeten if Necessary: If the berries are not sweet enough, sprinkle sugar on them and let them sit for about 10 minutes. This allows the juices to develop.
3. Prepare the Base: Cut the sponge cake into evenly sized cubes or slices. If using ladyfingers, ensure they are dry enough to hold up in layers.
4. Layer Components: In a glass trifle bowl, add a layer of sponge cake at the bottom.
5. Add Custard: Spoon a layer of vanilla custard over the sponge cake.
6. Layer Berries: Add a handful of mixed berries on top of the custard.
7. Top with Whipped Cream: Spread a layer of whipped cream over the berries, creating a light topping.
8. Repeat Layers: Continue layering in this order until the bowl is nearly filled—cake, custard, berries, and cream.
9. Final Touch: Finish with a generous layer of whipped cream on top. You can additionally decorate with a few whole berries or mint leaves for a pop of color.
10. Chill: Place the trifle in the refrigerator for at least an hour to allow flavors to meld.