Preheat oven to 350ᵒF/177ᵒC. Grease and dust with flour a 12-hole 3 ounce muffin pan. Set aside.
Cream butter until soft and fluffy. Add sugar and continue beating until smooth and lighter in color. Beat in egg and vanilla.
Sift dry ingredients together and add to the creamed mixture. Stir in chocolate chips and nuts.
Scoop out cookie dough into the prepared pan. Bake for 15 minutes or until lightly browned and set but still soft in the center.
Remove from the oven immediately, using a small steel measuring cup or the back of a spoon press down the center to create a well.
Cool in the pan for a few minutes then place on a wire rack to cool completely.