Preheat your oven to 350°F/175°C and line 3 baking trays with parchment paper
Whisk together your flour, baking soda, baking powder, cinnamon and nutmeg in a medium bowl. Set aside
In a small saucepan over medium-low heat, melt the butter. Once melted, increase the heat to medium and let the butter begin to foam. Keep cooking and stirring with a spatula, until the butter begins to brown and gives off a nutty smell (2-3 minutes). Pour into a medium bowl and let cool completely
Add in the sugars, vanilla and salt to the butter mixture. Whisk to combine.
Add in the egg and egg yolk and whisk until smooth and glossy
Pour in the dry ingredients and use a rubber spatula to combine until there are no more streaks of flour.
Add in your chocolate and butterscotch chips, but keep about ¼ cup of chocolate and butterscotch to the side.
Scoop out the cookie dough using a 1.5 tablespoon ice cream scooper and place on a lined tray. Once finished, gently press the extra chocolate on top of the cookie dough balls – this will give you those puddles of chocolate! Chill for at least 30 minutes or up to overnight
Bake the cookies 6 at a time for 10-12 minutes.