Langues de Chat

Instructions

1. Prepare the batter
   In a large bowl, cream together the softened butter and sugar until light and fluffy, about 3 minutes. Beat in the egg whites one at a time, then stir in the vanilla extract. If using, fold in the lemon zest.
2. Add dry ingredients
   Sift the flour and salt into the butter mixture and fold gently until well combined. The batter should be smooth and have a pipe-able consistency, but not be too runny. If it's too stiff, add a tablespoon of milk.
3. Prepare for baking
   Preheat oven to 350°F (180°C). Line baking sheets with parchment paper. Transfer the batter to a piping bag fitted with a plain 1/2-inch (1 cm) round tip or a small offset spatula.
4. Pipe the cookies
   Pipe 3-inch (7.5 cm) long thin strips of batter onto the prepared baking sheets, spacing them about 2 inches (5 cm) apart as they will spread during baking. Use a wet finger to smooth any peaks if necessary.
5. Bake the cookies
   Bake in the preheated oven for 8-10 minutes, or until the edges are golden brown. Watch carefully as they can burn quickly due to their thinness. The cookies should be slightly browned at the edges but still pale in the center.
6. Cool and store
   Allow the cookies to cool on the baking sheet for 1-2 minutes until firm enough to handle, then transfer to a wire rack to cool completely. Store in an airtight container for up to 1 week.