In a stand mixer, beat butter and confectioners’ sugar together on medium speed for about 3 minutes, until the mixture is very smooth. Beat in vanilla, then reduce mixer speed to low and add flour and cocoa powder, mixing only until it disappears into the dough.
Fold in the chocolate chips with a large spoon or spatula.
Gather dough and place in between two sheets of parchment paper. Roll the dough into a rectangle shape that’s 1/4 inch thick.
Refrigerate the dough for at least 2 hours (I transferred the parchment paper and dough onto a cookie sheet for support and stuck it in the fridge so that the dough would not break/bend).
After the dough is firm, preheat the oven to 325°F. Cut the dough into 1 1/2-inch squares.
Bake for 18 to 20 minutes, until they turn golden brown around the edges. Makes about 3 dozen.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.