In large bowl, cream butter and sugar until light and fluffy, beat in egg and vanilla.
In medium bowl, combine flour and baking soda, add to creamed mixture just until combined. Dough will be STIFF!
Stir in M&M bits, and nuts.
Spread dough into a lightly greased 9X13" pan.
Bake at 350 for 30-35 minutes, or until toothpick inserted into the center comes out with moist crumbs. DO NOT OVERBAKE!!!!
Cool completely, cut into bars. Store in tightly covered container.
Recipe submitted by Penny 9/30/00