In a medium mixing bowl, combine 1 tablespoon of softened butter with light brown sugar and gochujang. Mix until fully integrated and smooth, creating a thick caramel paste.

In a large mixing bowl, beat the remaining softened butter with granulated sugar and light brown sugar until creamy and fluffy, about 2-3 minutes. Add the large egg and vanilla extract, mixing until well combined.

Whisk together all-purpose flour, baking soda, kosher salt, and ground cinnamon before gradually adding the dry ingredients to the wet mixture, stirring just until combined.

Cover the cookie dough with plastic wrap and refrigerate for 10-15 minutes. Preheat your oven to 350°F (175°C) and prepare your baking sheets with parchment paper.

Remove the dough from the refrigerator and gently fold in dollops of the prepared gochujang caramel paste, creating a marbled effect.

Using a large cookie scoop, portion out the cookie dough onto the prepared baking sheets, leaving enough space between each cookie for spreading. Bake for 11-13 minutes.

Let the cookies cool on the sheets for about 3 minutes before transferring them to a wire rack to cool completely.