-
Preheat oven to 350 degrees and line a 9x9 baking dish with non-stick foil (or spray with baking spray).
-
In a bowl, cream butter, brown sugar, and granulated sugar together (you can do this with a hand mixer, standing mixer, or by hand with a rubber spatula). Once well combined, add in the egg, and mix until well combined.
-
Add in the baking soda, salt, espresso powder, and vanilla extract. Mix until combined.
-
Add in flour and cornstarch, mixing until combined.
-
Lastly, add in butterscotch chips and chocolate chips.
-
Press dough into your prepared baking dish (making sure the dough is spread in an even layer).
-
Bake for 20-22 minutes, or until the bars are lightly golden brown and set.
-
Allow to cool before slicing.
-
Enjoy!