Chocolate Chip Shortbread Cookies are all the goodness of melt-in-your-mouth shortbread combined with a little bit of chocolate, and then a little bit more.
In a large mixing bowl, beat 1 cup butter (softened) and 2/3 cup powdered sugar with a hand mixer until light and fluffy, about 2-3 minutes. Add 1/2 teaspoon vanilla extract and mix until combined.
Gradually add 2 cups all-purpose flour, mixing on low speed just until no streaks of flour remain. Gently fold in 3/4 cup mini chocolate chips.
Transfer the dough to a gallon-sized resealable plastic bag or place it between two sheets of plastic wrap. Roll the dough out to a thickness of 1/4 inch. Refrigerate the dough on a flat surface until firm, about 1 to 2 hours.
Once chilled, remove the dough from the plastic wrap. Use a butter knife to cut the dough into equal-sized squares or rectangles. Arrange the pieces on a parchment-lined baking sheet, spacing them about 1 inch apart.
Bake in a preheated oven at 325°F (165°C) for 18-20 minutes, or until the edges are just lightly golden. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Melt 8 ounces chocolate melting wafers in a microwave-safe bowl by heating them in 30-second increments, stirring well after each interval, until smooth. Dip one-third or one-half of each cookie into the melted chocolate, then place the cookies on parchment paper. Allow the chocolate to harden before serving or storing.