Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

Cream the softened butter, granulated sugar, and brown sugar together until light and fluffy, about 3 to 5 minutes.

Add in the egg and vanilla extract, mixing until fully combined, about a minute.

In another bowl, whisk together the flour, baking soda, and salt. Gradually add to the wet mixture, mixing until just combined.

Fold in the butterscotch chips until evenly distributed throughout the dough.

Drop tablespoonfuls of dough onto the prepared baking sheets, spacing them about 2 inches apart. Bake for 10 to 12 minutes, until edges are golden.

Let the cookies cool on the baking sheets for about 5 minutes before transferring to wire racks to cool completely.