Preheat the oven to 350℉. Line baking sheet(s) with parchment paper or silicone baking mats or spray with nonstick spray.
Cream together the butter, brown sugar, and white sugar with an electric handheld mixer on high speed for 1 minute. Add the eggs, vanilla, and salt and continue mixing until light and fluffy. Add the oats, flour, and baking soda and mix at low speed until just combined. Fold in the butterscotch chips.
Scoop the dough using a medium cookie scoop or teaspoon onto the prepared baking sheets, 12 cookies per pan. Bake cookies one pan at a time in the preheated oven for 9-12 minutes or until golden around the edges and just slightly soft looking on top. Let cool on the pan for a few minutes before transferring to a wire rack to finish cooling while you bake the remaining pans of cookies. Enjoy!
Notes
Add another ½ teaspoon of salt to the recipe if using unsalted butter.
In a pinch, you could use either kind of oat in the full amount of oats called for.
You could use semisweet, dark, milk, or white chocolate chips or peanut butter chips instead of butterscotch in this recipe.
Store baked and fully cooled cookies in an airtight container at room temperature for up to 4 days or freeze for up to 2 months.