Preheat oven to 350*. Have ready a 9 x 13 inch pan.
For Crust: Mix sugar and flour. Cut in butter, until mixture is crumbly. (a food processor works well here) Pat into pan. Bake 10 minutes.
While crust is baking, prepare the filling: Beat egg yolks, salt, sugar, flour, cream, and vanilla. Add rhubarb. Pour over crust. Bake 25 minutes. Lower oven temp. to 300*, bake 20 minutes more. Remove from oven.
Raise oven temp. back to 350*
While your bars are baking, prepare the topping: Beat ingredients intil stiff peaks form. Spread over hot filling. Bake for 15 minutes, or until meringue is nicely browned.