In a medium mixing bowl, combine the hulled and sliced strawberries with the granulated sugar. Gently stir the mixture until the strawberries are evenly coated in sugar. Set aside for about 15 minutes, allowing the strawberries to macerate and release their sweet juices.
While the strawberries are macerating, take another bowl and use a hand mixer or whisk to whip the heavy cream until soft peaks begin to form.
Next, add the mascarpone cheese and vanilla extract to the whipped cream. Carefully fold these ingredients together using a spatula until the mixture is smooth and well combined.
In a 9x9 inch baking dish, arrange a layer of ladyfinger cookies at the bottom, covering the base fully.
Spread half of the mascarpone mixture evenly over the layer of ladyfingers.
Then, layer half of the macerated strawberries on top of the mascarpone mixture, distributing them evenly.
Repeat the layering process with the remaining ladyfingers, followed by the rest of the mascarpone mixture, and finish with the remaining macerated strawberries.
Cover the baking dish tightly with plastic wrap and refrigerate for a minimum of 4 hours, or preferably overnight.
Just before serving, garnish the top of the icebox cake with fresh mint leaves.
Notes
For an elegant touch, consider slicing the cake into squares and serving on individual plates, accompanied by a drizzle of the strawberry juices from the bottom of the dish.