Preheat oven to 350°F (175°C).
In a bowl, mix flour, powdered sugar, and salt.
Cut in cold butter until the mixture resembles coarse crumbs.
Press firmly into a parchment-lined 9x13 inch pan
Bake for 15–18 minutes or until lightly golden.
Toss rhubarb with 1/4 cup sugar and let sit for 15 minutes.
In a separate bowl, whisk eggs, remaining sugar, flour, cream, vanilla, and salt until smooth.
Drain rhubarb and spread evenly over the baked crust.
Pour the custard mixture on top.
Bake at 350°F (175°C) for 35–40 minutes or until the center is set
Cool completely before cutting into bars. Dust with powdered sugar if desired.
