I'm planning to make a quiche, and the recipe calls for a lard/butter mixture in the crust. I don't have any lard. I don't have time to go to the butcher, and I don't want to use the supermarket stuff, which has some scary preservatives in it. Oh, and I'm allergic to soy, so no Crisco. And they've banned palm shortening from the Whole Foods where I live--not sure why. Sigh. I know I can use all butter, but I like the flakiness of a lard crust. What I do have is some leftover duck fat from Christmas--do you think I can use it as a substitute?