Combine egg, water, and vinegar in a bowl.
Whip with a fork until light and frothy. Set aside.
In separate bowl, mix together, flour, sugar and salt.
Using a paddle attachment on a mixer, or using a fork and mixing by hand, cut shortening into the flour mixture
Add wet ingredients to flour and shortening mixture and mix well.
When everything is incorporated, and the dough is slightly sticky, but not sticking to the edges of the bowl, roll your dough out so it is 1/2 centimeter thick.
A trick is to use a wet cloth to dampen the counter space you are working in, and put wax paper on top of the damp spot. This will hold it in place to make rolling easier.
Spray 3 12 hole regular sized muffin tins with non-stick cooking spray
Roll dough out in batches, and cut into 3-4 inch diameter circles to fill your muffin tins with a little over the edge.