Place the chilled heavy whipping cream, powdered sugar, and vanilla extract into a large, cold mixing bowl.
Beat the mixture on medium-high speed until stiff peaks form; be careful not to over-beat, or the cream will turn into butter.
Take your serving glasses and place a single layer of cake cubes at the bottom of each.
Spread a thin layer of ube halaya over the cake, using a small spoon to ensure even coverage.
Add a generous dollop of whipped cream on top of the jam layer, smoothing it out with the back of your spoon.
Repeat the layers—cake, ube, and cream—until the glasses are filled to the top.
Cover the glasses loosely with plastic wrap and refrigerate for at least 2 hours to allow the cake to absorb some moisture from the cream.
Before serving, top each glass with a sprinkle of toasted coconut and a few fresh berries for a pop of color.