Preheat oven to 350 degrees. Line a baking sheet with parchment paper. In a stand mixer with the paddle attachment cream butter and both sugars until light and fluffy, about 3 minutes.

Add in peanut butter and mix for 1-2 minutes.

Add in egg and vanilla. Mix until combined and clump free.

Add flour, salt and baking soda to the stand mixer on the lowest speed. Mix just until incorporated. Make sure not to overmix.

Fold in M & M's by hand.

Portion heaping tablespoon size cookies onto prepared baking sheet. Using your fingers gently flatten the cookies. This will help the cookies spread as they cook.

Bake cookies for 8-9 minutes or until lightly golden brown and firm on the edges. Remove from the oven and let set for 5 minutes on the baking sheet. Transfer to a cooling rack to cool completely. I always like to slightly under bake my cookies. They will continue to cook as they cool.

About 5-10 minutes before assembling remove the ice cream from the freezer. To assemble the ice cream sandwiches place one cookie upside down and top with a large scoop of ice cream (about 1/2 cup). Using a knife spread the ice cream to the edges making sure to work quickly. Top the sandwich with another cookie and press down gently. Place on a baking sheet with parchment paper and place in the freezer. Repeat with the rest of the cookies.