Heat oven 375*.
Grease a standard muffin tin and set aside.
In a medium bowl, whisk together Flour, Baking Powder, Baking Soda, and Salt.
For faster mixing, cream Shortening and Sugar for a minute using a handheld electric mixer or by hand.
Beat in Eggs and Vanilla Extract.
Add dry ingredients alternately with the Orange Juice. Mix, DON'T beat, the ingredients. When a few streaks of flour are showing, add in the Orange Zest and the Pecans, if using.
Fill the muffin cups 3/4 full. Bake for 18-20 minutes, or until light golden brown, a toothpick inserted in the center comes out with a few crumbs, and the muffins centers lightly spring back when touched. They should look like something you want to eat.
Cool the muffins before glazing. The recipe states you should wait 20 minutes. I'm not sure if I was close to that or not. If your muffins are too warm when you glaze them, the glaze will melt and drip right off of them. You don't want that. Check them after 10 minutes and see if they still feel atomic.