Preheat oven to 350 degrees. Lightly grease a 9x13 baking dish and set aside.
Place butter, PB, sugar, and vanilla in a stand mixer and combine until smooth. You may need to occasionally scrap down the side.
In a separate bowl combine remaining ingredients. Combine PB mixture & oat mixture. It will be VERY thick. Use a sturdy wood spoon or your stand mixer on low.
Once combine, fold in "optional" items. Pour into prepared pan. Spread evenly.
Bake for 20-25 minutes or until the bars are lightly brown along the edges.
Cool completely; cut into bars.
