Chocolate Filled Walnut-Oatmeal Bars

For Bars:

Preheat oven to 350 degrees. Blend together butter or margarine and sugar in a large bowl. Add eggs and vanilla and beat until light and fluffy. Stir together oats, flour, 1 cup walnuts, baking soda and salt and gradually add to butter mixture to form dough. Reserve 2 cups dough. Press remaining dough evenly over the bottom of a 15x10 inch jelly roll pan. Spread chocolate filling over dough. Crumble reserved dough over filling. Sprinkle with remaining 1/2 cup walnuts. Bake 25 minutes until top is golden brown. Cool completely in pan and cut into bars.

For Filling:

Melt butter in a medium saucepan over low heat. Stir in cocoa, sugar and condensed milk. Cook, stirring constantly, until smooth and thickened. Remove from heat and stir in vanilla.