Preheat your oven to 350°F (175°C).
In a bowl, mix 2 cups flour, ⅔ cup powdered sugar, and 1 cup softened butter until crumbly.
Press the mixture into a greased 9x13-inch baking dish to form the crust.
Bake the crust for 15 minutes, then set aside.
In another bowl, whisk eggs, white sugar, salt, ½ cup flour, and chopped rhubarb until well combined.
Pour the rhubarb mixture over the partially baked crust.
Return to oven and bake for another 30–35 minutes until the top is set and lightly golden.
Cool completely, then cut into bars and serve.