Preheat the oven to 350 degrees.
Using a food processor, blender, nut mill or knife, finely chop the pecans. Add the powdered sugar to the processor or blender (if that's what you used) and grind or chop. If done by hand, just mix together.
Mix the flour and salt together in a large mixing bowl. Drop in the chunks of butter and the vegetable shortening in teaspoon amounts. Begin to mix with your hands, until the butter and vegetable shortening are mixed in with the flour and salt. The mixture will turn into a coarse dough, with chunks of butter and shortening mixed throughout.
Add in the sugar and pecan mixture and work it all in. Crack the egg into the mixture thoroughly combine, using your hands. In less than a minute, the dough should be soft and malleable enough to be turned into a ball. Don't knead more than necessary, you just want it to come together into a homogeneous mass.
Butter a large cookie sheet. One by one, make small balls of dough with the palms of your hands. The dough ball should be between 1 and 1 1/2 inches wide. Place them on a baking sheet with about 1 inch in between the dough balls. Bake them for about 15 to 16 minutes, until they have a golden brown color.
Dust extra confectioners sugar over the top of the cookies and eat and serve.