- 1-3/4 cups (425 mL) all-purpose flour
- 1/2 tsp (2 mL) baking powder
- 1/4 tsp (1 mL) baking soda
- 3/4 cup (175 mL) butter, softened
- 1/2 cup (125 mL) icing sugar
- 1 egg yolk
- 1-1/2 tsp (7 mL) grated key lime zest
- 4 tsp (20 mL) key lime juice
- Sugar Coating:
- 1/4 cup (60 mL) granulated sugar
- Grated zest of 1 key lime (scant 1/2 tsp / 2 mL)
1. For Sugar Coating, in small bowl of food processor, whirl together 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. In small bowl, whisk together flour, baking powder and baking soda; set aside. In large bowl, beat together butter and icing sugar until light and fluffy; beat in egg yolk, lime zest and lime juice. Gradually stir in flour mixture.
3. 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–lined baking sheet. Bake in 300°F/150°C oven until edges and ridges are just starting to turn golden, 25 to 30 minutes. Roll in lime sugar while still warm; let cool on rack.