Mix all dry ingredients together.
Mix melted butter (cooled) with egg.
Mix dough well. Divide in two Rap in plastic Refrigerate for an hour.
Take out one of the dough balls. Roll out on parchment approximately 9 x 13, Use a 1.5 inch cookie cutter. Cut ONE cookie side out and weigh. It should weigh 6 grams. More than that will be too thick for the snap. Once you can assess that you have rolled the dough thin enough, continue to make cut-outs but leave them. Don't take out of the mold. You will need to place in freezer for about 15 minutes, so you can then easily remove each cookie.
Prepare baking sheet with parchment or silpat. You will probably bake 12 at a time. They don't spread much but leave about 2 inches between cookies.
Bake at 325 degrees F., 160 C. for ten minutes.
Remove cookies to rack to cool. Cool completely before filling. They will be soft, but will harden once cooled. Once, cooled, cookies will be easy to move and to fill. They should have a snap to them.