For a really impressive Christmas cookie, how about one containing a gem inside? A British online retailer, veryfirstto.com, did this last year with 3-carat diamonds (price tag for the set: 995,000 pounds), but we think less precious gems (garnets, topaz, amethyst or even aquamarines) could work just as well. Gather up all those loose stones you’ve got in a jar in the shop and order your own custom-made store-branded cookies. Sell them in sets of 12.