Shave off some twists of lime peel to trim the top of this cake. In a hurry? Use small slices of lime as a garnish.
Key limes, grown in Florida, are a fraction of the size of the limes that are usually seen in the grocery store and are more yellow than green in color. Fresh Key limes are available in specialty produce markets or gourmet food stores, but fortunately, bottled unsweetened Key lime juice is widely available. Look for it next to the bottled lemon juice.