Special equipment: a 9-inch springform pan
Preheat the oven to 350 degrees F.
Pulse the biscotti to fine crumbs in a food processor. Drizzle in the butter, add the salt and pulse until the mixture has the texture of wet sand. Press into the bottom of a 9-inch springform pan.
Bake for 8 minutes, until the crust smells toasted and is beginning to brown. Set aside to cool while you make the filling. Reduce the oven temperature to 325 degrees F.
In a stand mixer fitted with the paddle attachment, beat the cream cheese, mascarpone and sugar on medium-high speed until light and fluffy, about 3 minutes, scraping down the sides of the bowl occasionally with a rubber spatula. Add the salt, vanilla and lemon zest; beat on medium speed until combined. Add the eggs, one at a time, beating after each addition until just combined. Scrape down the sides of the bowl and mix again. Remove the bowl from the mixer and fold in the chocolate chips.
Pour the cream cheese mixture over the crust and spread evenly. Bake for 45 minutes, or until the center of the cake still moves just slightly.
Allow the cheesecake to cool on a wire rack for 1 hour. Cover with plastic wrap and refrigerate for at least 4 hours or overnight. Run a knife around the edge of the pan before releasing the collar.
Top each slice of cheesecake with a spoonful of cherries, if using.