01 - Toss the peach slices with lemon juice and sugar in a bowl. Set aside for 10 minutes to macerate and release natural juices.
02 - In a large mixing bowl, whip the cold heavy cream until soft peaks form using a hand mixer or stand mixer.
03 - Combine mascarpone cheese, sugar, and vanilla extract in another bowl. Mix until completely smooth and no lumps remain.
04 - Gently fold the whipped cream into the mascarpone mixture using a spatula until fully incorporated and creamy.
05 - Combine peach juice and schnapps (if using) in a shallow dish for dipping the ladyfingers.
06 - Quickly dip each ladyfinger into the peach juice mixture, ensuring they are moistened but not saturated or soggy.
07 - Arrange half of the soaked ladyfingers in a single layer at the bottom of a 9x7 inch serving dish.
08 - Spread half of the mascarpone cream evenly over the ladyfingers, then top with half of the macerated peach slices.
09 - Repeat with another layer of soaked ladyfingers, the remaining mascarpone cream, and the rest of the peaches.
10 - Cover the dish and refrigerate for at least 4 hours, or preferably overnight, to allow flavors to meld and texture to set.
11 - Garnish with fresh mint leaves just before serving.