For the shortcrust pastry: Knead all ingredients briskly in a mixing bowl or on a work surface to form a shortcrust pastry. Let rest in the refrigerator, covered with plastic wrap, for 2 to 3 hours before working. Add as little flour as possible when rolling out the dough. This is best done between two baking mats or a thicker vacuum bag (or stronger plastic wrap). Before continuing to work the dough, sweep off excess flour thoroughly with a flour whisk or wider brush. Cut out squares with a cookie cutter. Bake: 165 °C hot air, 10 to 12 minutes).
From the cooled cookies, spread half with Liptauer or spread of your choice and place a second square on top. Spread this one finely with basil pesto, decorate with sausage or cheese, etc.