Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the softened unsalted butter, light brown sugar, and granulated sugar. Beat on medium speed until light and fluffy, about 2-3 minutes.
Add the egg and vanilla extract to the butter mixture and beat until well combined.
In a separate bowl, whisk together the all-purpose flour, cornstarch, baking soda, cinnamon, and salt. Gradually add this dry mixture to the wet ingredients, mixing on low speed until just combined.
Gently fold in the butterscotch chips and honey roasted peanuts until evenly distributed throughout the dough.
Drop heaping tablespoons of cookie dough onto prepared baking sheets lined with parchment paper, leaving about 2 inches of space between each cookie.
Bake for 10-12 minutes, or until the edges are lightly golden and the centers appear set but slightly soft.
Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
