Preheat your oven to 350°F (175°C) and prepare a 9x13 inch baking pan lined with parchment paper.

In a saucepan, combine chopped rhubarb, sugar, and water over medium heat. Simmer for 8 minutes, then add cornstarch and cook for 2 more minutes.

In a mixing bowl, beat cream cheese until smooth, then add icing sugar and egg, mixing until combined and fluffy.

In another bowl, combine butter, flour, oats, brown sugar, and salt until crumbly. Press half into the baking pan for the crust.

Spread the cheesecake filling over the crust, then dollop the rhubarb compote on top, smoothing it out evenly.

Mix chopped walnuts into the reserved crust mixture and sprinkle over the rhubarb layer.

Bake for approximately 30 minutes, until golden brown and the sides are set with a slight jiggle in the center.

Cool completely in the pan, then lift out using the parchment overhang, slice, and refrigerate before serving.