Whenever you zest an orange, make sure to avoid the pith--the soft, white part between the orange peel and flesh--which is really bitter. All the natural oils and flavor are compacted in the orange part of the peel. To get maximal flavor out of the orange zest, the recipe starts by rubbing together the zest and sugar. The abrasive texture of the sugar will help draw out the flavor and oils from the orange peel. The cookies are not too thin and not too cakey; they should come out of the oven looking perfectly crisp on the edges and soft in the middle. I always recommend baking and serving cookies fresh, rather than preparing them days ahead. If you want to give yourself a head start, whip up a batch of the cookie dough, scoop it and freeze it, then bake straight from frozen when your guests have arrived. You’ll get the freshly baked cookie experience without any fuss.