Pick mustang grapes before their seeds have fully formed. Wear gloves to protect sensitive skin.
Place two to three parts grapes, one part sugar and on part water in a pot and simmer.
Once the grapes becomes soft, stir in half a stick of butter. a dash of salt and one tablespoon of cornstarch or flour.
Pour mixture into an unbaked piecrust and top with remaining dough. Pinch edges together and perforate top crust.
Bake for about one hour at 350 degrees or until crust is golden brown. Remove from the oven and allow to cool.
Top with a dash of cinnamon and whipped cream or ice cream if desired. Enjoy!