1. Start by preparing the berry compote. In a small saucepan, combine the mixed berries with 1/4 cup sugar and 1/4 cup water. Cook over medium heat, stirring occasionally, until the berries break down and the mixture thickens slightly—about 10 minutes. Remove from heat and let cool.
2. While the compote cools, prepare the custard. In a medium saucepan, heat the milk and 1/2 cup heavy cream over medium heat until it just starts to simmer. Do not let it boil.
3. In a bowl, whisk together egg yolks, 1/3 cup sugar, and cornstarch until pale and smooth.
4. Slowly pour about half of the hot milk mixture into the egg yolk mixture, whisking constantly to temper the eggs. Then pour everything back into the saucepan.
5. Cook over medium heat, whisking continuously, until the custard thickens and coats the back of a spoon—about 5-7 minutes. Remove from heat and stir in vanilla extract. Transfer to a bowl, cover with plastic wrap directly on the surface to prevent a skin, and chill for at least 2 hours.
6. When ready to assemble, whip the remaining 1 cup of heavy cream with powdered sugar until soft peaks form.
7. In a large glass trifle bowl or individual glasses, begin layering: start with a layer of cake cubes, then a layer of custard, followed by a spoonful of berry compote, and a handful of fresh berries. Repeat the layers until the bowl is full, ending with whipped cream and a few berries on top.
8. Garnish with fresh mint leaves if desired, and refrigerate for at least 1 hour before serving to allow flavors to meld.

One of my favorite memories is how Mama Lou let me sprinkle the final layer of berries while Ouma carefully placed mint leaves. It was our way of adding a little extra love and personality to the dessert.