1. To make the dough: Place the butter in the work bowl of a food processor fitted with the metal blade and process, scraping down the sides of the bowl as needed, until creamy. Add the confectioners’ sugar and process to blend well. Add the ground almonds, salt, and vanilla and continue to process until smooth, scraping the bowl as necessary. Lightly stir the eggs together with a fork and, with the machine running, add them to the work bowl; process for a few seconds to blend. Finally, add the flour and pulse until the mixture just starts to come together. When the dough forms moist curds and clubs and then starts to form a ball, stop! — you don’t want to overwork it. The dough will be very soft, and that’s just as it should be. (If you want to make the dough in a mixer, use the paddle attachment. First beat the butter until it is smooth, then add the remaining ingredients in the order given above. Just be careful when you add the flour — you must stop mixing as soon as the flour is incorporated.)