In a large mixing bowl, whisk together the all-purpose flour and salt, ensuring even distribution. In a stand mixer, cream the unsalted butter and confectioners’ sugar together until light and fluffy, about 3–5 minutes. Add in the orange zest and vanilla extract, mixing until fully incorporated. Gradually add the flour mixture, blending until a soft dough forms, ensuring no dry pockets remain.

Turn the dough out onto a clean work surface and shape it into a log about 12 inches long and 2 inches wide. Wrap the log tightly in plastic wrap and refrigerate for at least 2 hours or overnight.

Preheat your oven to 325ºF (160ºC). Using a sharp knife, slice the chilled dough into 1/4-inch thick rounds and place each cookie about 1 inch apart on a parchment-lined baking sheet. Bake for 15–17 minutes or until the edges are just firm and the centers are set.

While the cookies cool, prepare your dark melting wafers by melting them according to the package instructions. Dip each cookie halfway into the smooth chocolate and allow excess to drip off. Place the dipped cookies back onto the parchment paper to set.