In a bowl whisk together the flour, sugar, salt. Cut the butter into pieces and add to the flour mix. Using a pastry blender, two forks, or your hands and work the butter into the flour until the mixture is sandy with some larger pieces of butter left (about the size of peas).

Add the vinegar and ice water one tablespoon at a time while stirring. Add enough water just until the dough comes together.

Transfer the dough onto a counter and gently shape into a circle. Wrap the dough in plastic wrap and refrigerate 1 hour or up to overnight.

Preheat the oven to 400 degrees.

Stir together the sliced plums, sugar and cornstarch. In a separate bowl beat together the egg with 1 tablespoon water.

Cut the chilled dough into 8 pieces. Roll each one out into a thin circle about 6 inches across. Place 1/8 of the filling into the middle of each circle. Brush the edges with the beaten egg. Fold the dough over the filling to create a half circle. Crimp the edges with a fork.

If the dough begins to soften, refrigerate the turnovers until the dough firms up before baking.

Bake for 15-18 minutes or until the crust is golden brown. Allow to cool and then serve with ice cream!