Place the oven rack in the lower half of the oven and preheat to 325°F.

Place the animal crackers in a food processor and pulse until they are fine crumbs.  Add in the sugar and pulse again.  Add the butter in a steady stream and continue to pulse until the mixture starts to come together, about 10 1-second pulses.

Transfer the crumb mixture to a 9-inch springform pan and press evenly into the bottom.  Bake until it is golden brown, about 13-15 minutes.  Remove from the oven and allow to cool.  Once cool, wrap the pan with 2 18-inch pieces of foil.  Set in a roasting pan and set aside.

To make the filling, place 1/4 cup of the sugar and the lemon zest in a food processor and process until the sugar turns yellow and fragrant.  Add in the remaining sugar and pulse a few times to combine.

In the bowl of a stand mixer, beat the cream cheese for about 5 seconds.  With the mixer on low, add in the lemon sugar in a steady stream, then switch to medium and beat until creamy and smooth, about 3 minutes.  Scrape down the sides of the bowl.  Reduce the speed to medium-low and add the eggs, 2 at a time, scraping down the bowl in between additions.  Add in the lemon juice, vanilla and salt and mix to combine.  Add in the cream and beat to combine, another 5 seconds.  Scrape the bowl again to make sure everything has been incorporated and pour into the springform pan.

Place the pan in the oven and carefully add enough water to the roasting pan to make it halfway up the sides of the springform pan.  Bake until the center is slightly jiggly and the sides start to puff and the surface is no longer shiny, about 55 to 60 minutes.  Turn off the oven and prop the oven door open with a towel or wooden spoon.  Allow the cake to cool in the oven for 1 hour.

Remove from the roasting pan, remove the foil, and transfer to a wire rack.  Run a small paring knife around the edges of the cake and let it sit at room temperature for 2 hours.

While the cheesecake is baking, make the lemon curd.  Heat the lemon juice in a small pan over medium heat until it is hot, but not boiling.  In a small bowl, whisk the eggs.  Gradually whisk in the sugar.  Whisking constantly, slowly pour the hot lemon juice into the egg mixture, then pour the mixture back into the pan.  Continue to cook over medium heat, stirring constantly, until the mixture reaches 170°F, or until it is thick enough to coat the back of a spoon.   Remove the pan from the heat and whisk in the butter until it is melted.  Stir in the cream, vanilla and salt.  (If you have lumps in the curd, pour through a fine mesh strainer to strain any lumps.)  Pour the curd into a small nonreactive bowl.  Cover the surface of the curd directly with plastic wrap and refrigerate until needed.

When the cheesecake is cool, top it with the lemon curd while still in the springform pan.  Cover tightly with plastic wrap and refrigerate for at least 5 hours, but 24 hours is better.