Preheat your oven to 350 degrees. Use the convection bake function if you have it.
Using a hand mixer or a stand mixer fitted with the paddle attachment, cream the softened butter, brown sugar and granulated sugar until smooth. Scrape down the bowl once complete.
Next, add the vanilla extract, eggs, salt, baking soda and baking powder. Mix until combined, then scrape down the bowl again.
Add the flour and oats in 2-3 portions, mixing after each addition.
Add the chocolate and butterscotch chips and mixing until combined. Then scrape down the bowl.
Line a 9x13" baking pan with parchment paper and press the oatmeal cookie dough evenly throughout the pan. I like to use another sheet of parchment paper to press the dough throughout the pan since the dough is sticky.
Sprinkle additional chocolate and butterscotch chips over the top of the dough, if desired, then bake for 25-30 minutes or until the edges of the bars look crispy and the middle is not very jiggly (a little movement in the middle is OK).
Remove them from the oven and allow them to cool to room temperature before removing the bars from the pan.
