Preheat your oven to 350°F (175°C). In a mixing bowl, combine the crushed cookies with melted butter until the mixture resembles wet sand. Firmly press this blend into the bottom of a lined mini muffin pan to form even bases. Bake for 5-7 minutes, until lightly golden and fragrant, then allow to cool completely.

While the crust cools, prepare the rhubarb topping. In a medium saucepan over medium heat, combine chopped rhubarb with sugar and a splash of water. Stir as it cooks for 6-10 minutes until jammy. Let it cool to room temperature.

In a mixing bowl, beat the softened cream cheese and sugar together until smooth. Add egg, vanilla extract, and a pinch of salt, continuing to mix until fully incorporated.

Spoon the cream cheese filling into each cooled crust, filling them to about three-quarters full. Top with a dollop of the warm rhubarb mixture, swirling for a marbled effect if desired.

Bake at 325°F (165°C) for 10-14 minutes until edges are set, and centers are still jiggly. Let them cool at room temperature before chilling in the refrigerator.

Chill in the fridge for at least 2 hours before serving. Pop them out of the muffin pan and present to guests.