Basque Lemon Cheesecake

Ingredients

• 270 grams sugar
• Finely grated zest of 3 lemons
• 1 teaspoon salt
• 800 grams cream cheese, cut into 2-inch pieces, at room temperature
• 227 grams mascarpone cheese, at room temperature
• 6 large eggs, at room temperature
• 240 ml heavy cream, at room temperature
• 100 ml fresh lemon juice, divided
• 2 teaspoons vanilla extract
• 32 grams all-purpose flour

Directions

1. Heat the oven and prepare the pan: Arrange a rack in the upper third of the oven and heat to 230°C (210°C fan). Crumple up two large pieces of parchment paper (each at least 15 inches long), then smooth flat again and arrange perpendicularly. (Crumpling the parchment helps it mold better to the pan and stay in place.) Press the two pieces into the springform pan, smoothing along the bottom to ensure it’s completely flat and up the sides to flatten all creases. Use a pair of scissors to trim away any parchment that extends more than ½ inch above the top of the pan. Set the pan aside.
2. Make the batter: In the bowl of a food processor with a minimum 14-cup capacity, combine the sugar, lemon zest and salt and process until the sugar looks like wet sand and is very fragrant, about 30 seconds. Stop the motor and add the cream cheese and mascarpone and process again, pausing once to scrape down the sides, until the mixture is completely smooth and free of lumps and the sugar is dissolved (rub a dab between your fingers to check for graininess), about 30 seconds.
3. With the motor running, add the eggs one at a time, processing for a few seconds between additions, then slowly stream in the cream, 85 ml of lemon juice and vanilla. Add the flour and process briefly. Stop the motor, scrape down the sides and process again just until the batter is completely smooth.
4. Bake: Pour the batter into the prepared pan and transfer to the oven. Bake until the top is risen, set, and starting to brown, and the batter still moves like liquid underneath the surface (like a waterbed) when jiggled, 30 to 35 minutes. Take the internal temperature with an instant-read thermometer, inserting it into the center of the cake about ⅔ down. When the cake is done the temperature should register somewhere between 60 - 65°C (the center will be looser and creamier on the lower end of the range, more set and slightly drier on the higher end, see Tip). Continue baking, checking every few minutes, until it reaches the desired doneness, another 5 to 10 minutes, but you might need to bake for longer, depending on your oven.
5. Make the lemon glaze: In a small bowl, combine the remaining 15 ml lemon juice and 1 tablespoon sugar and stir with a pastry brush to dissolve the sugar. Set the glaze aside.
6. Broil the top: Remove the cheesecake from the oven. If the top is dark brown and burnished all over, move on to the next step (this will depend on your oven). If it’s only partially browned, turn on your broiler and let it preheat for a few minutes while the cheesecake cools. Return the cheesecake to the oven and broil, maintaining a constant eye on it, until the entire surface turns a deep, shiny dark brown (but not blackened!), 10 to 20 seconds. Remove from the oven immediately and set aside.
7. Brush on the glaze and cool: While the cheesecake is still hot from the oven, brush the lemon glaze over the surface, using all of it. Let the cheesecake cool in the pan until the sides are warm but not hot, about 2 hours, then transfer to the refrigerator (it will settle gradually). Refrigerate until it’s cold and completely set, at least 12 hours and up to several days (if refrigerating for longer than 12 hours, cover the surface loosely).
8. Serve: Remove the cheesecake from the refrigerator, remove the base from the sides of the pan, and gently peel the parchment away from the cheesecake. (The cake is very solid once cold, so you should be able to flip the cake over to do so.) Cut into slices with a hot knife, cleaning the knife in between cuts. For the best texture, let the slices come to room temperature before serving.

Notes:

• For a looser, creamier center on the finished, cooled cake, aim for an internal temperature of 60°C or a few degrees above. If you prefer the center to be more set and slightly drier, bake the cake until the center reaches closer to or just at 65°C.
• DO AHEAD: The cheesecake will keep in the refrigerator, wrapped in plastic, for 4 days.