In a small saucepan set over medium heat, melt the butter. Swirling the pan occasionally, continue to cook the butter. It should become foamy with audible cracking and popping noises. Once the crackling stops, continue to swirl the pan until the butter develops a nutty aroma and brown bits start to form at the bottom. Once the bits are amber in color, about 2 to 3 minutes after the popping stops, remove from heat and pour into a mixing bowl. Stir in the granulated sugar and dark brown sugar. Allow to cool for about 20 minutes to room temperature.

With an electric mixer, beat the cooled butter, granulated sugar, and brown sugar until well combined, about 1 to 2 minutes. Add the eggs, yolk, and vanilla, beating until combined. On low speed, gradually beat in the flour mixture. Stir in the chocolate chips and butterscotch caramels. Wrap dough in plastic wrap and refrigerate for at least 24 hours but no more than 72 hours.

Bake for 12-15 minutes, or until golden brown. Remove from oven and let cool for 2 minutes before removing to wire racks to cool completely. Serve or store in an airtight container for 3 days.