Cut in the butter with a pastry blender until mixture resembles course sand.
In a small bowl combine the egg, vinegar and water. Add to the dry ingredients and blend with a pastry blender until moist.
Divide in half and roll out one half on a lightly floured surface. Once it has reached the desired size, carefully lift one half off the counter and drape over your rolling pin. Then carefully move the whole thing over to your pie plate and place inside.
Then roll out the top crust and slice into strips to make the lattice, set aside while you make the filling. TO MAKE THE FILLING
In a medium mixing bowl, combine all the ingredients and stir until mixed.
Pour into the prepared pie crust and dot with the butter.
Carefully weave the lattice on the top.
Bake for about 25-30 minutes and then check the crust to make sure it is not getting to dark. If it is, place a piece of foil over the top to keep it from getting darker. Bake another 20 minutes.
Remove from oven and allow to cool to room temperature to serve.
Recipe by Foods of Our Lives at https://www.foodsofourlives.com/2013/08/grandmas-sour-cherry-pie/