In your electric mixer cream the butter with the sugars. Add the egg and vanilla extract, mixing to combine. Mix in flour, pudding mix, kosher salt, and baking soda. Fold M&M’s into the cookie dough by hand (to prevent breakage).
Using a cookie scoop, drop the dough onto a baking sheet lined with parchment paper or a silpat mat.
Lightly sprinkle the scoops of dough with sea salt.
Bake cookies for 10-12 minutes until cooked through. Transfer to a cooling rack and allow to cool before eating!