Preheat oven to 350 degrees and line baking sheets with parchment paper.
Beat butter and sugars until creamy. Add egg and vanilla. Add flour, pudding mix, baking soda and salt till combined. Fold in chips and M & M's by hand.
Use a large tablespoon to scoop dough onto sheet. Bake 11-13 minutes until edges are golden. Cool on cookie sheet and remove to rack.