In a medium saucepan, combine 12.3 oz of trimmed rhubarb, 1 cup of granulated sugar, 1/2 tsp vanilla extract, 1 tsp fresh lemon juice, and a pinch of salt. Cook over medium heat for about 10-15 minutes, stirring occasionally until the rhubarb breaks down and the mixture thickens. Once thickened, blend until smooth, then divide the jam into two portions: one for the filling and another for the topping. Chill in the refrigerator to set.

In a mixing bowl, combine 4.7 oz of finely crushed graham crackers, 1 1/2 tbsp granulated sugar, a dash of cinnamon, and a pinch of salt. Pour in 3.5 oz of melted unsalted butter and mix until the mixture resembles wet sand. Firmly press this mixture into the bottom of a lined 9x13 inch dish. Place the crust in the freezer for 30 minutes to set.

Heat 3 oz of heavy cream in a small saucepan over low heat until warm, then remove from heat. Sprinkle 1 1/4 tsp of gelatin powder over the cream, whisking gently until dissolved. Allow this mixture to cool at room temperature for about 10 minutes.

In a separate mixing bowl, whip the remaining 6.5 oz of heavy cream with an electric mixer on medium speed until soft peaks form, about 3-5 minutes. Refrigerate until needed.

In a large mixing bowl, beat 8 oz of room temperature cream cheese with 1/3 cup of granulated sugar, 1/2 tsp vanilla extract, and 1/4 tsp salt until completely smooth and creamy. Gently fold in the cooled gelatin mixture and the reserved rhubarb puree. Finally, fold in the whipped cream until just combined.

Pour the cheesecake filling over the chilled crust, spreading it evenly. Swirl the remaining rhubarb puree into the filling for a marbled effect. Cover and refrigerate for at least 3 hours.

Let the cheesecake sit at room temperature for 10-15 minutes before serving for easier slicing. Slice and serve with optional garnishes.