I adapted this recipe from Titli Nihan, a very funny British cook on youtube. Always use EAGLE brand sweetened condensed milk. It is slightly offwhite and creamy instead of grey and sticky. For the grated lime peel, you can get small hand graters or "zesters." or simply use a fine cheese grater, but this must be done by hand by holding and rolling the lime around. I suppose you can peel the lime and use a food processor but then you have no garnish. Do not substitute lime for key lime. You can get Nellie and Joe's just about anywhere they sell RealLemon.
Melt butter and add to crushed graham crackers in pie plate (I prefer pyrex or corning ware for a soft crust. Metal pans will dry out crust.) Fold/cut crumbs into butter until completely moistened and smooth around plate with the back of a large spoon. Work quickly or the butter will cool and stick to your spoon leaving holes in the crust.
Beat eggs 1 min.
Add condensed milk. Beat 3-4 minutes
Mix in lime juice and zest with whisk or fork. (Zest will get hung up on the blades of a mixer.)
Bake 10-15 min. until surface springs back when lightly touched with finger. You can get a good idea if it is ready by popped bubbles on the surface and a slightly dried look. If it is glossy and wet it is not done and will stick to your finger when touched.
Cool 15-20 minutes and then refrigerate for about 2 hours before serving. Can be stored, covered in fridge for about 4 days.