¾ pound unsalted butter, at room temperature
1 cup sugar, plus extra for sprinkling
1 teaspoon vanilla extract
3½ cups all-purpose flour
¼ teaspoon salt
6 to 7 ounces semisweet chocolate, finely chopped
1. Preheat the oven to 350 degrees F.
2. In the bowl of an electric mixer fitted with a paddle attachment, mix together the butter and 1 cup of sugar until they are just combined. Add the vanilla. In a medium bowl, sift together the flour and salt, then add them to the butter-and-sugar mixture. Mix on low speed until the dough starts to come together. Dump onto a surface dusted with flour and shape into a flat disk. Wrap in plastic and chill for 30 minutes.
3. Roll the dough ½-inch thick and cut into 3 by 1-inch fingers, either using a cookie cutter, pastry wheel, or pizza cutter. Place the cookies on an ungreased baking sheet and sprinkle with sugar. Bake for 20 to 25 minutes, until the edges begin to brown. Allow to cool to room temperature.
4. When the cookies are cool, place them on a baking sheet lined with parchment paper. Put 3 ounces of the chocolate in a glass bowl and microwave on high power for 30 seconds. Stir with a wooden spoon. Continue to heat and stir in 30-second increments until the chocolate is just melted. Add the remaining chocolate and allow it to sit at room temperature, stirring often, until it's completely smooth. Stir vigorously until the chocolate is smooth and slightly cooled; stirring makes it glossier.
5. Dip ½ of each cookie into the chocolate to coat, letting the excess drip off. Set back on the parchment-lined sheet and let sit at room temperature until chocolate is set. Store at room temperature in a tin.