For the crust: Preheat the oven to 320 degrees F. Grease a 9-inch springform pan with butter, line with parchment then wrap the outside with foil.
Pulse the graham crackers, sugar and salt in a food processor until fine crumbs.
Mix the crumbs with the melted butter in a medium bowl. Press on the bottom and a little bit up the sides of the prepared pan. Bake until golden brown, 10 to 12 minutes.
For the cheesecake: Fill a medium saucepan halfway with water and bring to simmer over medium heat. Place a heatproof bowl on top to create a double boiler. Add the cream cheese, cream, butter and 1/4 cup of the sugar to the bowl and let melt. Once everything is melted, use a whisk to blend. Remove from the heat.
Add the egg yolks, one at a time, to the cream cheese mixture. Sift the flour into the batter. Whisk and blend together. Then pass the batter through a fine mesh strainer to a clean bowl to remove any lumps. Stir the lemon zest and lemon juice into the batter. Whisk well to blend and set aside.
Add the egg whites to a large mixing bowl and sprinkle with the cream of tartar. With a hand mixer, whisk until the egg whites become foamy, like dense bubble bath. Start to slowly add the remaining 1/4 cup sugar. Once all the sugar has been added, increase the mixer speed to high and beat the egg whites until soft peaks. Whisk for another 30 seconds to firm up the egg whites a little more. In batches, fold the egg whites into the cream cheese mixture.
Pour the batter into the crust and tap the pan on the counter a few times to release any air pockets. Place the pan into a roasting pan and add water until it reaches halfway up the cake pan. Bake until cooked through and golden brown on top, 70 to 75 minutes. Turn off the oven and leave the oven door ajar for 15 to 20 minutes with the cake inside. Remove from the oven and let the cake cool to room temperature.
For the strawberry sauce: Meanwhile, combine the strawberries, sugar, water, lemon zest and lemon juice in a medium pot over medium heat. Cook and stir until the strawberries are soft, about 10 minutes. Let cool slightly, then pour into a blender and blend until smooth. Cool before serving. Serve with the cheesecake.