- Preheat the oven to 350F, rack in the middle. Line 2 baking sheets with parchment paper and set aside.
- In a bowl, whisk together the flour, salt, baking powder, cocoa and espresso powder; set aside., In another bowl beat together the brown sugar, whole egg and egg yolk till creamy (a hand mixer works fine for this or you can use a stand mixer). Next, add in the peanut butter and mix until the mixture is creamy.
- Add in the flour mixture and mix just until blended. Scrape off the beaters as you don’t want to lose any cookie batter!
- Add in the melted butter and chocolate chips and mix together with a spatula. Using a medium-large cookie scoop, scoop out the cookie dough. With damp hands, place the cookie dough in your hand and gently shape to a ball. Place on to the prepared pans leaving a 1” space. Normal sized pans get 12-16 per tray.
- Bake for 11-14 minutes or until the cookie is set but still slightly soft. They will firm up while cooling. Place the tray on a cooling rack and wait 3 minutes before placing the peanut butter egg in the middle of the cookie. Gently place the egg on the cookie and push down slightly. Allow to cool on the pan for at least 5 more minutes before transferring to the cooling rack to cool completely. Do not force them off of the tray.
- Once they are completely cool, transfer to an airtight container.