01 - Toss peach slices with lemon juice and sugar in a bowl. Set aside for 10 minutes to macerate and release natural juices.
02 - Using a hand mixer or stand mixer, whip cold heavy cream in a large mixing bowl until soft peaks form.
03 - Combine mascarpone cheese, sugar, and vanilla extract in a separate bowl. Mix until completely smooth and creamy.
04 - Gently fold the whipped cream into the mascarpone mixture using a spatula until fully incorporated and uniform in texture.
05 - Combine peach juice and peach schnapps (if using) in a shallow dish suitable for dipping 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 sliced macerated peaches.
09 - Repeat layers with remaining soaked ladyfingers, followed by the rest of the mascarpone cream and peach slices.
10 - Cover the dish and refrigerate for at least 4 hours, preferably overnight, to allow flavors to meld and texture to set.
11 - Garnish with fresh mint leaves just before serving. Cut into squares and serve chilled.