*The lemon zest is important, so be sure to include it. I like to use a water bath (see above for explanation) but it's not required. Preheat the oven to 350 F. Combine the crust ingredients, if using. Press into a parchment-lined 8x8 pan. Meanwhile, combine remaining ingredients in a blender or food processor until smooth. (Don't over-beat, which could cause cracking.) Pour over the crust, and bake 25 minutes. Do not open the oven door (not even to check), but turn off heat and let sit 8 minutes. Take out the still-undercooked bars and let cool completely, then refrigerate a few hours until firm. Leftover bars can be refrigerated or frozen.View Nutrition Facts