Preheat oven to 350 degrees F. and line a 9x13-inch baking dish with parchment paper.
Cream butter and sugars into a large mixing bowl or stand mixer until well combined. Beat in egg and vanilla. Slowly add flour, pudding mix, baking soda and salt. Stir until dough starts to form then stir in chips and candy cane bits. Press into prepared baking dish and bake for 25-30 minutes until golden brown on top and baked through. Let cool completely before cutting into squares.