Pie dough: Measure out flour and butter in a food processor fitted with a knife. Drive to a crumbly mass. Add water and vinegar and run until dough is formed into a ball. Flatten out the dough and place it in a plastic bag. Leave to cool for about 30 minutes.
Filling: Remove the kernels, cut the apples into chunks and cut the chunks into slices.
Melt the apple slices in the butter and lemon juice until they soften. Taste with sugar. Mix in the mash and raisins. Let the filling cool.
Place the filling in a pie mold, about 24 inches in diameter. Pick up the dough on the floured back table and roll it out to a plate, about 24×24 centimeters. Trace out four strips, about 4-5 inches wide, to the grid.
Trace the rest of the dough into narrower strips, 3 inches wide, to the edges.
Place the dough strips on baking sheet paper and leave to cool for about 15 minutes. It will be easier to work with the dough strips when the dough is chilled.
Set the oven to 175 degrees. Place the wide strips as a grid over the filling. Place the narrower strips as a border around the pie and press.
Brush the grill and edge with whisked egg and sprinkle sugar over.
Put the pie in the center of the oven and bake for about 35 minutes.
