Thin and chewy with crisp edges; buttery, sweet, salty and filled melty pools of chocolate and toffee. The optional splash of bourbon both complements and balances the sweet and salty parts of the cookie.
In a medium mixing bowl beat the room temperature butter and sugar on medium high speed until light and fluffy. On low speed, beat the egg, yolk, extract and bourbon until well combined.
Cover the cookie dough with plastic wrap. Chill the dough in the fridge for 2 hours or up to 48 hours.Pull dough out about 15 minutes before baking to allow the dough to soften at room temperature.