Rhubarb Cheesecake Squares

2. In a medium bowl, whisk together the flour, oats, brown sugar, and salt.

3. Add the cold butter to the dry ingredients and use a pastry blender or your fingers to work it into the mixture until it resembles coarse crumbs.

4. Stir in the chopped walnuts.

5. Press half of the crumb mixture into the prepared baking pan.

# Preparing the Rhubarb Layer

1. In a large bowl, combine the chopped rhubarb, granulated sugar, water, and cornstarch.

2. Let it sit for about 15 minutes, until the rhubarb starts to release its juice and the mixture becomes syrupy.