In a medium bowl, combine the sliced strawberries, granulated sugar, and lemon juice. Stir gently to combine, then let sit for about 20-30 minutes to macerate. This will enhance the sweetness and create a syrup.
In a separate bowl, use an electric mixer to whip the heavy cream, powdered sugar, and vanilla extract until soft peaks form. Be careful not to over-whip.
In a large trifle dish or individual serving glasses, layer the dessert. Start with a layer of cake cubes, followed by a layer of the strawberries (including some syrup), and then a layer of whipped cream.
Repeat the layers until all ingredients are used, ending with whipped cream on top.
Chill the trifle in the refrigerator for at least 1 hour to allow the flavors to meld.
Just before serving, garnish with fresh mint leaves for a pop of color and freshness.
Notes
Chill the trifle for at least 1 hour before serving for best flavor.