In a medium bowl, combine sliced strawberries with granulated sugar and lemon juice (if using). Toss gently to coat, then let macerate for 15-20 minutes until juicy. Reserve a few perfect slices for garnish.

In a large chilled bowl, beat cold heavy cream with powdered sugar and vanilla extract using an electric mixer on medium-high speed until stiff peaks form, about 3-4 minutes. Be careful not to over-whip.

Arrange cake cubes in an even layer in the bottom of a 9x13 inch glass baking dish. Lightly drizzle with simple syrup or strawberry juice to moisten.

Spoon half of the macerated strawberries and their juices evenly over the cake layer, ensuring good coverage to the edges.

Spread half of the whipped cream evenly over the strawberry layer using an offset spatula or the back of a spoon.

Repeat the layers: remaining cake cubes, remaining strawberries, and finish with the remaining whipped cream.

Cover with plastic wrap and refrigerate for at least 1 hour (or up to 4 hours) to allow flavors to meld. Before serving, garnish with reserved strawberry slices, toasted almonds, and mint leaves.