Preheat your oven to 350°F (175°C). In a mixing bowl, combine flour and sugar, then cut in cold butter until the mixture resembles coarse crumbs. Press into the bottom of a greased 9x13-inch baking dish. Bake for about 10 minutes until lightly golden.

In a separate bowl, whisk together the sugar, flour, and salt. In another bowl, beat the eggs then add the heavy cream, whisking until smooth. Combine wet and dry ingredients gently, then fold in the diced rhubarb.

Pour the custard mixture over the crust, spreading it evenly. Bake for 40-45 minutes until set around the edges but slightly jiggly in the center. Allow to cool at room temperature.

Beat cream cheese, sugar, and vanilla extract until light and fluffy. Fold in whipped cream gently to create a creamy topping.

Spread the cream cheese topping evenly over the cooled custard layer. Cover with plastic wrap or foil and refrigerate for 2-3 hours to set.

Once chilled, slice using a sharp knife and serve cool for the best flavor and texture.