In a large bowl mix together the boiling water, shortening, milk, salt, sugar, and potato flakes. Place in the refrigerator until thoroughly chilled.
After dough is thoroughly chilled, add the flour, using a pastry blender to cut in.
Divide dough into 3 equal size portions. Form into 3 logs. Chill thoroughly in the refrigerator.
Heat an electric griddle to 375 degree F (190 degrees C).
Divide logs into 8 pieces. Roll to about the size of a 10 inch tortilla. Work additional flour into rounds as needed. Use care to press lightly with rolling pin when forming into rounds as they are much more tender than pie dough. The weight of a large rolling pin is nearly enough.
Bake on the griddle until each round feels dry but not crisp. Turn frequently.
Cool on cloth. Cover with an additional cloth. Stack pieces on top of each other as they are baked. The steam will create a more tender product.