Sift together flour, salt.
Using an electric mixer beat the butter and sugar together until light and fluffy—5 minutes.
Add vanilla bean, mix well then add eggs and lemon zest. Beat to combine.
Slowly add the flour mix until the dough is smooth.
Separate the dough and wrap it in 3 separate pieces. Place in the fridge and chill for at least one hour.
When ready to bake, preheat the oven to 375 degrees F. Line several cookie sheets with parchment paper.
Remove one disk at a time. Flour a work surface and roll the disk out to 1/8 to 1/4 inch thick. The more times you roll out the dough the tougher it gets. Use a thin spatula to transfer the cookies onto the baking sheets.
Bake for 8-10 minutes. (edges just starting to brown)
Cool completely on the cookie sheets before moving.
Decorate with Royal Icing