Cream butter, sugar, vanilla and lime zest together until homogenous. Add egg yolk slowly and scrape.
Add sifted flour and salt. Do not over mix.
Lime Ganache
Make ganache one day in advance.
Cold infuse lime with cream and milk overnight. Strain.
Bring cream, milk and trimoline to a boil. Pour over melted chocolate in three stages mixing well between each addition making sure to achieve a proper emulsion. Add butter. Blend to homogenize.
Assembly
Roll sweet crust out to 1/8” thick. Cut with a 2” ring cutter. Place cookies on perforated silpat and bake @ 350 for 12 min or until golden brown. Allow to cool.
Pipe lime ganache onto one baked cookie. Top with another baked cookie and garnish with chocolate stripes.