In a small bowl add egg and stir with a fork. Stir in vinegar and then water. In a separate bowl add the lard and 4 cups flour.

Cut the lard into small pieces using a pastry cutter. Add the liquid and continue to cut the lard into the mixture adding more flour as needed.

Do not overwork. Stop when the dough comes together into a sticky ball. Divide into half and wrap in cello. Place in the refrigerator for 30 min. to 1 hour. If only making one pie put the other half into the freezer for later use. Thaw in the refrigerator when you want to use it later.

Meanwhile, in a large bowl combine blueberries with the cherry pie filling. Set aside. Preheat oven to 425F.

When the dough has rested remove from the refrigerator and roll out on a floured surface. Roll out half the pastry to fit in an 11″ inch pie plate.

Place in the pie plate and trim the edges. Place in the pie filling. Roll out the remaining dough and cut long strips the size of the pie for the lattice. Weave the lattice top and seal the edges with a little dab of water.

Whisk the egg and 1 tsp. water together. Lightly brush the lattice top with the egg mixture and sprinkle with sugar.

Bake in the preheated oven for 15 min. Then reduce heat to 350F and continue baking until golden and the filling has thickened for 45-50 min.

Cool completely on a rack.