Add the Valrhona Ivoire 35% white chocolate to a small mixing bowl. In a large microwave safe measuring cup (or on the stove), heat the heavy cream until it starts to simmer. Pour the hot heavy cream over the white chocolate, and stir until the chocolate is melted and the mixture is smooth. Set aside.
Add the cream cheese, sugar and cornstarch to a stand mixer fitted with the paddle attachment (or to a large bowl with a hand mixer.) Beat the ingredients together on medium speed for 2 minutes, until smooth and fluffy.
Add the three eggs, vanilla, and lemon juice into the cream cheese and beat the mixture on low speed until just incorporated.
Add in the melted white chocolate mixture and mix again on low speed until just combined. Tap the mixing bowl on the counter a few times to get rid of air bubbles in the batter.
Pour ½ of the cheesecake batter over the baked shortbread crust. Spoon the cherry jam over the cheesecake, then use a knife to gently swirl the cherries into the batter. Cover the cherries with the remaining cheesecake batter.
Fill a 10×15" baking dish, or any larger pan that can reasonably fit the 9" springform inside of it, a third of the way with hot water. If desired, wrap tin foil around the bottom of your springform pan to avoid the possibility of water seeping into the springform.
Place the springform pan into the larger pan, then place the whole thing into the oven. Bake for 70-80 minutes, or until the cheesecake only slightly wobbles and reaches an internal temperature of at least 170°F / 76°C. If the cheesecake starts to brown on top, gently place a piece of tinfoil over the top of the pan.
Once the cheesecake is fully cooked, turn off the oven and leave the door slightly ajar with the cheesecake in it for 1 hr. Once the hour has passed, start making the cherry mousse.