Dec. 27, 2020 2:48 pm ET The Christmas celebration inevitably gives way to the post-Christmas cleanup, replete with such less-than-merry tasks as taking down the decorations, putting away the good china and, of course, getting rid of the tree. Julia Georgallis, a 32-year-old, London-based industrial designer-turned-trained baker, is calling upon holiday revelers to consider an alternative —at least when it comes to that last step. Her suggestion: using a Christmas tree, particularly its ever-fragrant needles, to make Christmas tree pickles. Or Christmas tree hot-smoked fish. Or perhaps best of all, Christmas tree ice cream. “For some reason, when you mix Christmas trees with dairy, it’s kind of unbelievable,” says Ms. Georgallis, who has spent the last five years concocting various recipes from these trees and hosting sold-out culinary events with her resulting dishes. Her latest effort: a newly published cookbook called “How to Eat Your Christmas Tree.”