Preheat oven to 350 degrees and line baking sheet with parchment paper.
In the bowl of a stand mixer, combine butter, sugars, and pudding mix until fluffy.
Add salt and vanilla extract.
Stir on low just until combined.
Continue stirring and add egg and egg yolk one at a time.
Then add flour and baking soda to bowl and stir just until dough forms.
Add peppermint baking chips to dough and stir until combined.
Form three tablespoons of dough into balls and place on cookie sheet.
Bake for 12-14 minutes.
Remove from oven and let cool on baking sheet.
Makes about 20 large cookies.