Preheat your oven to 350°F (175°C). This ensures your cookies start baking at the right temperature for that perfect chewy texture.
In a large mixing bowl, combine the softened butter, granulated sugar, and light brown sugar. Using an electric mixer, cream them together until the mixture is light and fluffy. This usually takes about 2-3 minutes.
Add the eggs, one at a time, mixing well after each addition. Then, pour in the vanilla extract and mix until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, and salt. This step helps to evenly distribute the baking soda and spices throughout the flour.
Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix; a few flour streaks are perfectly fine.
Using a spatula, fold in the quick-cooking oats and butterscotch chips until evenly distributed throughout the dough.
Using a cookie scoop or a spoon, drop rounded tablespoons of dough onto a lined baking sheet, spacing them about 2 inches apart.
Bake in your preheated oven for 10-12 minutes or until the edges are lightly golden but the centers still look soft. They will continue to cook on the baking sheet after you remove them from the oven.
Allow the cookies to cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy them warm or store them for later!