Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with sugar until fluffy. Add in egg and mint extract until smooth.
Add in the flour mixture, mix until it is fully combined. Fold in the M&Ms and crushed Oreo cookies. Place the powdered sugar into a shallow dish.
Roll the cookie dough into balls, and roll each one into the powdered sugar. Place the cookies onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.
