How do I get vegetarian tamales to come out fluffy? I'm a vegetarian, so naturally I don't use lard when making the masa for tamales. I've experimented with butter, non-hydrogenated vegetable shortening, and solid coconut oil. I've tried beating the dough for a long time in my stand mixer, as I've read some suggestions that that is the key to make a fluffy dough. I've also tried both fresh masa and MaSeCa.

My tamales are ok, but I inadvertently had a bite of a lard-based tamale last year, and it was drastically fluffier and lighter than anything I've achieved. I don't know if the difference is the choice of fat, or if the restaurant that made them employs a better mixing technique. Help?
You can use Crisco All-Vegetable Shortening: its is on PETA's (People for the Ethical Treatment of Animals) shopping list of baking goods, but can work just as well for frying as lard.