In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.

Beat in the egg and vanilla extract until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Stir in the butterscotch syrup and heavy cream until the dough comes together. If desired, fold in the butterscotch chips for added flavor and texture. Then, refrigerate the dough for 1 hour.

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

Roll the dough into 1 inch balls. Place on the prepared baking sheet, leaving at least 3 inches between each cookie.

Bake the cookies in the preheated oven for about 10 to 12 minutes or until the edges are lightly golden brown.

Remove the cookies from the oven and let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.

Once fully cooled, make the butterscotch buttercream. Add the softened butter to a stand mixer. Beat until fluffy.

Then, add in the melted butterscotch chips. Beat until combined.

Sift in the powdered sugar and salt. Then, add in the extracts. Stir until light and fluffy.

Finally, frost each cookie once completely cooled!