Pie Crust:

Chill all ingredients, including the flour and vinegar. Combine the flour, salt and sugar. Cut in shortening with a pastry blender until the mixture resembles cornmeal. In another bowl, mix water and vinegar with the beaten egg. Add the liquid mixture, 1 tablespoon at a time, to the flour mixture, tossing with a fork to form a soft dough.

Filling:

Preheat oven to 450 degrees F.

Peel and slice apples. Sprinkle with lemon juice. Combine dry ingredients in large bowl and add apples. Toss to mix. Add vanilla and cream. Melt butter in heavy skillet. Add apple mixture and cook approximately 8 minutes, to soften apples. Turn into pie shell.

Streusel Topping:

Combine the flour and sugar. Mix in butter with fork until coarse crumbs. stir in the crushed toffee bars. Sprinkle over pie. Add top crust. Seal, flute edge and vent top. Brush with beaten egg white and sprinkle with sugar. Bake for 15 minutes. Reduce heat to 350 degrees F and bake 45 minutes longer.