1In a large mixing bowl, use a hand mixer to beat together butter and powdered sugar until light and fluffy. Add in vanilla extract and beat until combined.
2Add in flour and mix just until flour disappears. Fold in mini chocolate chips.
3Transfer dough to a gallon-sized resealable plastic bag, or place between two layers of plastic wrap. Roll until 1/4 inch thick. Refrigerate on a flat surface until firm.
4Remove dough from plastic and use a butter knife to cut into equal-sized squares or rectangles. Transfer cut pieces to a parchment lined baking sheet.
5Bake at 325 degrees until edges are just lightly kissed with brown.