To start, melt butter in a medium-sized pot over medium heat. Make sure it’s completely melted but not bubbling, as we want to keep it smooth.
Next, remove the pot from heat. Stir in the packed brown sugar and granulated sugar until well combined. You’ll notice the mixture becoming shiny as the sugars dissolve into the butter.
Now, add in the egg and egg yolk, along with the vanilla. Mix the ingredients until the batter lightens in color, indicating that it’s well blended.
Pour in the flour, baking soda, salt, and ground cinnamon. Stir gently but thoroughly to ensure you have a smooth batter without any lumps.
Preheat your oven to 325 degrees Fahrenheit while you finish preparing the dough.
Stir the butterscotch chips into the batter. Let this mixture sit for 10 to 20 minutes to allow the flour to soak and the batter to thicken. This step is crucial for achieving the perfect cookie texture.
While the batter sits, line two baking sheets with parchment paper. This prevents the cookies from sticking and makes cleanup a breeze.
Using a 1 and 1/2 tablespoon cookie scoop, place rounded dollops of cookie dough onto the prepared pans, leaving enough space between each scoop for spreading.
Now it’s time to bake! Put the sheets in the oven and bake for 8 to 9 minutes. Rotate the sheets halfway through to ensure even baking. The cookies should look cooked around the edges but still undercooked in the center; this is exactly what you want!
Once baked, leave the cookies on the hot pans for 5 to 7 minutes. This allows them to firm up before moving them. Carefully transfer them onto cooling racks to cool completely before storing in air-tight containers.
