4 tablespoons unsalted butter, melted, plus softened butter for preparing the pan
1 cup graham cracker crumbs (about 5 ounces)
3 tablespoons brown sugar
1/2 teaspoon ground cinnamon
Pinch of kosher salt
1 1/2 pounds cream cheese, at room temperature
1/2 cup whole milk ricotta
1/2 cup crème fraiche
1 cup granulated sugar
4 large eggs, at room temperature
2 teaspoons vanilla extract
1 teaspoon lemon zest
1/4 teaspoon lemon extract
Pinch of kosher salt
1 1/2 cups heavy whipping cream
1 tablespoon powdered sugar
1 teaspoon vanilla extract
2 cups fresh blueberries
To make the blueberry swirl sauce: In a small saucepan, cook the blueberries, granulated sugar, and lemon zest over medium-low heat until the berries are tender and the sugar dissolves, about 5 minutes. Allow to cool slightly and then blend the berries with a blender or immersion blender until pureed.
To make the graham cracker crust: Position an oven rack in the center and preheat the oven to 350°F. Grease an 8 x 3-inch springform cake pan with softened butter and line the bottom with parchment paper.
In a food processor, mix together the graham crackers, melted butter, brown sugar, cinnamon, and salt. Pour the mixture into the prepared pan and press it out in an even layer. Bake for 10 to 15 minutes, until it starts to look lightly toasted. Remove from oven. Lower the oven to 325°F.
To make the cheesecake batter: In a stand mixer fitted with the paddle attachment, mix the cream cheese on medium speed for about 1 minute. Scrape down the sides, add the ricotta, and mix for another 30 seconds. Add the crème fraiche and mix for another 30 seconds, then scrape down the sides of the bowl. Add the granulated sugar and mix until it’s uniform and well combined. Add the eggs one at a time, scraping down the sides after each. Add the vanilla, lemon zest, lemon extract, and salt. Mix for 30 seconds.
Pour one-third of the cheesecake batter over the baked crust. Drizzle 3 tablespoons of the blueberry sauce over the batter. Use a skewer or knife to gently swirl the sauce into the batter. Pour half of the remaining cheesecake batter over the swirled blueberry sauce and repeat the swirling with another 3 tablespoons blueberry sauce. Add the remaining cheesecake batter and finish by swirling 3 tablespoons blueberry sauce on top. Reserve any remaining blueberry sauce for serving.
Place the cheesecake on a cookie sheet in the center of the oven. Place a second sheet on a lower rack and fill with boiling water. Bake for 60 to 75 minutes (the timing will greatly depend on the temperature of the ingredients). The cheesecake will soufflé as it bakes, which is normal for this style of baking. Once the top of the cake is set, remove from the oven and gently run a knife blade around the edge of the pan. Allow to cool to room temperature before refrigerating.
Chill for several hours or overnight. Run a hot knife blade around the outer edge of the cake, then remove the sides of the springform pan. Carefully slide the cheesecake onto a serving plate.
To make the toppings: In a stand mixer fitted with a whisk attachment, whip the cream, powdered sugar, and vanilla on medium-high speed until soft peaks form, about 3 minutes.
Top the cheesecake with the whipped cream and blueberries before serving. I used a pastry bag fitted with a leaf decorating tip to make the ruffles. Serve with the remaining blueberry sauce.