Peanut Butter Fingers

3/4 cup peanut butter
1/2 cup butter
1 cup sugar
1 1/4 cup brown sugar
4 eggs
1 tsp. vanilla
1 1/2 tsp. soda
1/4 tsp. salt
3 cups flour
4 cups rolled oats
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1/2 cup peanut butter
Mix together all ingredients except 1/2 cup peanut butter. Bake in ungreased 11 x 17 baking sheet at 350* for 12 minutes. Do not over bake. It will finish baking in pan. Let cool slightly. Whip 1/2 cup peanut butter and spread over peanut butter fingers. Frost with chocolate frosting.