Heat oven to 425° F.
In a large mixing bowl, mix the flour and the sugar. Then add the egg yolks, butter and salt, combine well. Stir in the milk.
In a separate bowl, beat the egg whites to stiff peaks. Fold them gently into the mixture.
Place the rhubarb in the bottom of an unbaked 9 inch deep dish or 10 inch pie shell.
Pour the mixture over the rhubarb. Bake for 15 minutes at 425° reduce the heat to 350 ° and bake about 40 minutes or until the top is browned and the filling is set.