1 ½ sticks butter, softened
¾ cup creamy peanut butter
1 ¼ firmly packed light brown sugar
1 large egg
1 tsp. vanilla
1 ½ cups all ~ purpose flour
1 tsp. baking soda 
¼ tsp. salt
2 cups M&M's chocolate mini baking bits, divided 
2 quarts vanilla ice cream, slightly softened
Preheat oven to 350º. In large bowl cream the butter, peanut butter, and brown sugar until light and fluffy; beat in the egg and vanilla. In medium bowl combine flour, baking soda and salt; blend this into the creamed mixture. Stir in 1 ½ cups of the M&Ms. Shape dough into 1 ¼ ~ inch balls.
Place about 2 inches apart on ungreased cookie sheets. Gently flatten to about ½ ~ inch thickness with fingertips. Place 7 or 8 remaining M&M's on each cookie; press them in lightly. Bake 10 to 12 minutes or until edges are light brown. Do not over bake. Cool about 1 minute on cookie sheet; remove and finish cooling on wire racks.
Assemble cookies in pairs, place about ½ cup ice cream;  between cookies  and press together lightly. Wrap each sandwich in plastic wrap; freeze until firm. Makes about 24 ice cream sandwiches.