In a mixing bowl, cream softened butter, both sugars, and peanut butter.
Add egg and vanilla then mix well.
Stir flour, oats, baking soda, and salt into the creamed mixture.
Spread batter into a greased 13×9 baking dish and sprinkle with chocolate chips.
Bake at 350ºF for 20-25 minutes or until lightly browned.
Icing:
While bars are baking, whisk together icing ingredients and set aside. After bars are baked and have cooled for 10 minutes, pipe/drizzle icing onto bars