Add the key lime zest to the sugar and massage well to release the aroma and oil from the zest.
1½ cup Granulated sugar, 1 tablespoon Key lime zest
Beat the room-temperature butter and sugar for 2 to 3 minutes until all creamy and light in colour.
1 cup Butter
Add the egg, yolk, vanilla extract, and key lime juice and mix well.
1 Egg, 1 Egg yolk, 2 tablespoon Key lime juice, 2 teaspoon Vanilla extract
Sift the flour, baking soda, salt, and cream of tartar. Add this mixture to the above mixture and gently mix. Do not overmix. Roll the cookie dough into small balls the size of a small tangerine.
3 cups All-purpose flour, 1½ teaspoon Cream of Tartar, ¾ teaspoon Baking soda, ¼ teaspoon Salt
Pulse the crackers in a food processor to reach a fine crumb, and roll the cookie dough balls into the cookie crumbs.
½ cup Graham Cracker crumb
Place the cookie dough balls on the lined baking sheets, leaving at least two inches between them. Bake them for 8-10 minutes or until their edges look set and slightly golden.
Remove them from the oven and immediately go around them with a round cookie cutter to reshape them. While they are still hot, sprinkle more graham cookie crumbs on them. Let them cool down on the baking sheet for 10 minutes, then transfer them to a cooking rack to cool down thoroughly.