Preheat oven to 350 degrees F. Lightly grease an 8x8 pan with non-stick cooking spray. Line with parchment for easy removal.
In a separate bowl combine the dry ingredients of flour, salt, baking soda,and rolled oats together, set aside.
In a large mixing bowl, using mixer or by hand beat together the butter, brown sugar, and white sugar until smooth and light.
Add egg and vanilla and beat in.
Add dry ingredient mixture to wet mixture and continue mixing together until combined. Fold in chocolate and butterscotch chips, reserving some for the top of the bars.
Spread or press cookie dough into the bottom of the prepared pan.
Sprinkle remaining butterscotch and chocolate chips on top.
Bake for 25 to 30 minutes or until golden brown. After 25 minutes, check cookie bars by giving the pan a little shake. If it jiggles in the middle, put the pan back in and try again every 5 minutes until there is no longer any jiggle and it’s better to not overbake.
Remove from the oven and let cool 10 minutes before cutting.
Double recipe for large batch in 9x13 pan