Preheat the oven to 350 F/180 C. Line two baking sheets with parchment paper and set them aside.
Melt the butter then stir in the coffee grounds. Set aside to cool to room temperature, about 5 minutes.
Scrape all of the butter into a mixing bowl and add the sugar and brown sugar. Whisk vigorously to combine for 1 minute.
Mix in the egg, egg yolk, and vanilla for 30 seconds.
Mix in the flour, baking soda, and salt until almost combined. Then fold in the chocolate chips and butterscotch chips. Set the bowl of dough aside for 10 minutes, this will firm up the dough and make it easier to scoop.
Scoop the cookie dough with a 2-tbsp cookie scoop onto the prepared baking sheets (13 cookies max on each tray). Bake on the middle rack of the oven for 8-9 minutes, or until the edges are golden. Straight out of the oven, press more chocolate and butterscotch chips on top. Then let the tray cool completely on the wire rack before removing them.
Store leftover butterscotch cookies in an airtight container at room temperature for 2-3 days. If you wish to freeze the dough balls for later, store them in a freezer bag or airtight container. When you are ready to bake them, let the dough come to room temperature before baking!