Preheat the oven to 325ºF (160ºC) and line two baking sheets with parchment paper.
Whisk together the flour, oats, baking soda, and salt in a bowl to combine. Set aside.
Place the butter and both sugars in a mixing bowl. Use a hand or a stand mixer to beat the butter and sugars together until the mixture is light and creamy, about 2 to 3 minutes.
Add one egg to the butter and beat until well combined. Repeat with the second egg, then mix in the vanilla extract.
Using a wooden spoon or hard-edged rubber spatula, stir the flour mixture into the butter mixture.
When the cookie dough is about halfway mixed, add the butterscotch chips.
Continue to stir and fold until the flour is just combined. Ideally you want a few streaks of flour remaining to ensure the cookies stay chewy. Over-mixing can lead to tough cookies.
Use a small cookie scoop to scoop the dough. Press the scoop firmly against the side of the mixing bowl to fully fill the scoop with dough. Place 12 cookie dough scoops on each baking sheet.
Gently press the top of each cookie with the heel or palm of your hand to flatten it into a 2 to 2 ½ inch (5 to 6 cm) round. Rub a bit of water on the heel of your hand to help prevent the dough from sticking.
Once all of the cookies are flattened, place them in the preheated oven and bake for 12 to 14 minutes. When the edges show even the slightest hint of browning, remove the cookies from the oven.
Remove the cookies from the oven and transfer the pans to wire racks. Leave the cookies on the pans to cool completely before storing.
Notes
If your butter is too soft the cookies may spread. If you are unsure, place the flattened unbaked cookies in the fridge to chill for an hour before baking.
We bake with large eggs.
We used clear vanilla in this recipe, as you can see in the pictures. Use any vanilla extract you like or have on hand.
Cooling the cookies completely on the baking sheet retains moisture which means a chewier cookie. If you want less-chewy cookies, cool them directly on a wire rack instead.
Substitutions
Use up to half whole wheat pastry flour for a higher fibre cookie.
Instant oats can be used in a pinch, but they won’t have the same texture and chew as large flake oats.
Mix Ins & Variations
Try almond, orange, brandy, or even maple extract in place of some of the vanilla. We recommend trying 2 teaspoons of vanilla and up to 1 teaspoon of an alternative (less for almond).
Add up to 1 cup of chopped pecans, walnuts, or hazelnuts. Macadamia nuts would also be nice.