Grandma Couch's Peanut Butter Squares

3/4 c butter
1/2 c sugar
2 c brown sugar
2 eggs
2 tsp vanilla
3/4 c peanut butter
3/4 tsp baking soda
1/4 tsp salt
1 1/2 c flour
2 c oatmeal
Mix in order listed, spread on large prepared cookie sheet, bake at 350 for 10 minutes, frost with a thin layer of peanut butter and a thin layer of chocolate frosting