Key Lime Cookies

Directions

1. 1
   Sugar Coating: In small bowl of food processor, whirl sugar and lime rind until sugar is fine. Transfer to bowl; cover and let stand for at least 2 hours or overnight. (If sugar clumps, break up into powder.).
2. 2
   Whisk together flour, baking powder and baking soda; set aside.
3. 3
   Beat butter and icing sugar until light and fluffy; beat in yolk, lime rind and juice. Gradually stir in flour mixture.
4. 4
   Transfer dough to pastry bag fitted with 1/2-inch/ 1 cm star tip (or plastic bag with corner cut out). Pipe out 1-1/2-inch/4 cm long cookies onto parchment paper-lined baking sheet.
5. 5
   Bake in 300°F/150°C oven until edges and ridges are just starting to turn golden, 25 to 30 minutes.
6. 6
   Important -
7. 7
   Roll in lime sugar while still warm; let cool on rack.
8. 8
   Makes about 3 dozen cookies.