Blend the shortening and the flour with a pastry cutter, or two knives, until you've created a uniform mixture that is crumbly and about the size of frozen peas.
In a separate bowl, mix 1 egg, 1 tbsp white vinegar and 2 tbsp cold water. Add to shortening and flour mixture.
Mix all ingredients together, but only until just mixed and no more.
The key to flaky pastry is not to overhandle the dough.
For ease of handling, make a ball of the dough, wrap in cellophane and place in freezer for 10-15 mins. Roll out dough onto floured surface to about the thickness of a CD case.
Using either a cookie cutter or something like a jar lid, cut out circles from the dough. Press dough circles into a muffin pan.
In another bowl, mix well corn syrup, brown sugar, melted butter and egg. Add vanilla and stir in raisins.
Spoon filling into pastry shell to just below the rim.
Bake at 400 for about 10 mins until golden brown.
Makes about a dozen tarts.