Combine egg yolks and sugar in a large bowl; stir well. Add remaining ingredients to the bowl and stir to combine. Transfer to a pastry-lined pie pan. Dot the top with a tablespoon or two of butter and stick it in a preheated 450-degree oven for 10 minutes. After 10 minutes, reduce the oven temperature to 350 degrees. Bake another 20 minutes (or until rhubarb softens). Remove pie from oven.

To make meringue:
3 egg whites, room temperature
1/2 teaspoon vanilla
1/4 teaspoon cream of tartar
1/4 cup sugar

Combine egg whites, vanilla, and cream of tartar in a mixing bowl. Beat until soft peaks form. Add sugar a little at a time, continuing to beat until you have stiff peaks. Spread meringue on top of filling and seal well. Bake another 10-15 minutes at 350 degrees. Cool. Chill to store.

You can find my pie pastry recipe on Farm Bell Recipes here:
Foolproof Pie Crust