Peanut Butter Fingers (I'm becoming world-famous for this one!)

1 c. butter
1 c. sugar
1 c. brown sugar
2 eggs
1/2 t. vanilla
1 c. peanut butter
1 t. soda
1 t. salt
1-1/2 c. flour
1-1/2 c. oats

Mix together and spread on a large cookie sheet. Bake at 375° for 10-15 minutes. (Won't be solid yet.) Cool, spread with peanut butter. Frost with chocolate frosting. Cut in squares.