Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large bowl, beat the softened butter, brown sugar, and granulated sugar together until light and fluffy—about 2-3 minutes.

Mix in the egg and vanilla extract until well combined.

In another bowl, whisk together the flour, baking soda, and sea salt, then gradually add it to the butter mixture, stirring until just combined.

Gently fold in the butterscotch chips into the cookie dough until evenly distributed.

Use a cookie scoop or tablespoon to portion the dough onto the prepared baking sheet, leaving space between each cookie.

Sprinkle a hint of sea salt on top of each cookie before baking.

Place the cookies in the oven and bake for 10-12 minutes or until the edges are golden but the center is still soft.

Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.