Add one full egg and an egg yolk and mix until everything is well combined.
Add the dry ingredients and mix to combine, then fold in the chocolate chips and marshmallows.
After chilling, roll cookie dough into balls and align on a tray - 6 to each tray.
Bake chocolate chip marshmallow cookies for 12 minutes then allow to cool slightly for transferring to a cooling rack.
Allow cookies to cool completely before serving - they will be fragile!
A couple of minutes before the cookies are finished baking, press a few extra marshmallows and chocolate chips into the tops for a gorgeous appearance.