Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking pan.
Prepare the shortbread crust: In a medium bowl, cream together the softened butter and powdered sugar until light and fluffy. Add the flour and salt, mixing until the dough forms. Press the mixture evenly into the bottom of the prepared pan.
Bake the crust: Place the pan in the preheated oven and bake for about 15-20 minutes, or until lightly golden.
Prepare the rhubarb filling: In a separate bowl, combine the chopped rhubarb, granulated sugar, cornstarch, vanilla extract, and beaten eggs. Mix until well combined.
Pour the rhubarb mixture over the baked shortbread crust, spreading it evenly.
Bake again: Return the pan to the oven and bake for an additional 25-30 minutes or until the filling is set and slightly firm to the touch.
Cool and Serve: Allow the bars to cool completely in the pan before slicing them into squares. Dust with powdered sugar before serving for an added touch!
