-
Stack two baking sheets together and line the top with parchment paper. You will need to repeat this for each batch.
-
In a mixer bowl, using a whisk attachment, whisk egg yolks and sugar until thick and pale, 1 to 2 minutes. Slowly blend in softened butter and vanilla.
-
Gradually add flour and salt, blending until dough is thick and stiff. If it is still quite soft add a bit more flour, a few tablespoons at a time. Knead dough gently and briefly on a lightly floured work surface. Then wrap dough well and refrigerate 45 minutes.
-
Preheat oven to 325°F
-
On a lightly floured surface, roll dough to 3/4 inch thickness. Cut into 3 inch round cookies and place on prepared baking sheet. With tines of a fork make a criss cross pattern on the dough.
-
For glaze, in a small bowl whisk egg yolks with water. Brush each cookie generously with egg wash mixture.
-
Bake until golden on top and browned around the edges, 50 to 55 minutes. Let cool completely on baking sheets.