Lemony Sandwich Cookies: sunny and lemony melt-in-your-mouth sandwich cookies with fresh lemon juice and lemon zest in both cookie dough and filling!
Cover baking pans with baking paper and leave aside.
For the filling, use small pot and slowly boil egg, egg yolk, sugar and vanilla extract. Stir constantly for 3 minutes until the filling becomes thick.
To assemble the cookies, use one whole cookie and one with a hole. Spread filling on the whole cookie and gently press the other one to it. ½ tsp of filling is enough to assemble each sandwich cookie.
Dust with icing sugar before serving, optional.