Preheat oven to 350°F.
Combine flour, oats, baking powder and salt in a bowl and set aside.
Cream the peanut butter, butter, and both sugars in large mixing bowl with electric mixer on medium-high speed until fluffy. Beat in egg and vanilla. Using lowest speed of mixer or by hand, stir in the flour mixture.
Stir in chocolate chips and peanut butter chips. Form mixture into 1-inch balls. Place 3 inches apart on nonstick baking sheets and flatten with tines of fork in criss-cross pattern. Bake 10 to 12 minutes or until edges are lightly browned and centers are still soft.
As soon as you pull the cookies from the oven, scatter holiday M&Ms on top. Cool 1 minute on baking sheet; transfer to wire racks. Cool completely. Makes about 36 cookies depending on what your idea of a 1 inch ball is.