Sieve gluten free flour, xanthan gum, baking soda and salt into a mixing bowl. Whisk together ensuring ingredients are well mixed. Set this aside for later.
Place the melted butter, almond butter, cream cheese, brown sugar, caster sugar and vanilla extract in the bowl of an electric mixer. Mix at a medium speed for 3 minutes.
Add the egg and mix at a low speed until incorporated. Repeat with the egg yolk.
Add the flour mixture you prepared earlier to the mixer bowl. Mix on a low speed until just combined, stopping to scrape down the sides if necessary.
Finally, mix through the chocolate chunks on a low speed until evenly incorporated.
Cover the bowl and chill in the fridge for at least 4 hours.
Once ready to bake, preheat the oven to 170°C. Roll the dough in evenly sized balls (each cookie should be approx 60-65g) and place on a lined baking tray. Make sure to leave enough room for spreading between each dough ball.
Bake for 11-12 minutes.
If adding extra chocolate chunks, push them gently onto the top of each cookie while they are still hot.
Leave to cool for approx 30 mins. The cookies will be very soft when fresh out of the oven and firm up as they cool.