Vinegar Pie

As we were reading Little House in the Big Woods, I was struck by Ma's Christmas baking. Rye 'n Injun bread, dried berry pies, and... vinegar pie? Intrigued, I looked up the recipe, and here it is. The recipe site avers that the pie is unusual but tasty. I plan to spring it on unsuspecting friends for Thanksgiving. If it's good it will be a hit, and if it's just too odd it will simply be a historical curiosity on the dessert table. Try it yourself and let me know what you think.

1 c. sugar
3 heaping tbsp. all-purpose flour
1 c. cold water
3 egg yolks
1 whole egg
2 tbsp. butter
6 tbsp. vinegar
1 (9 inch) pie crust, baked

Instructions:
Mix sugar and flour in saucepan.
Add water, egg yolks (reserve egg whites), whole egg, butter and vinegar.
Cook until thick.
Pour into baked 9 inch pie shell.

For Meringue:
Beat reserved egg whites until stiff.
Add 4 tablespoons sugar, spread over pie.
Brown meringue lightly.