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

Cream together softened butter, granulated sugar, and brown sugar in a large mixing bowl for about 2-3 minutes until fluffy.

Add in the egg and vanilla extract and mix on low speed until thoroughly combined.

Whisk together all-purpose flour, baking powder, and salt in a separate bowl, then gradually mix into the wet ingredients.

Scoop equal portions of the dough, roll into balls, flatten gently, and place on the prepared baking sheet.

Bake for 12-13 minutes until lightly golden around the edges, then cool on the baking sheet for 10 minutes.

Beat softened butter for the frosting, then add powdered sugar, vanilla extract, and heavy cream until fluffy.

Mix in butterscotch syrup and beat until light and airy.

Pipe or spread frosting onto the cooled cookies and top with sprinkles if desired.