Preheat your oven to 160C (320F) and line two baking trays with baking paper.
Beat butter and sugar in the bowl of a standmixer fitted with the paddle attachment, or use a handheld mixer and a large bowl. Beat until light and fluffy.
Add the egg and cream into the mixture. Scrape down the sides of the bowl so that the batter is thoroughly mixed.
Add vanilla extract and peanut butter and beat until combined.
Whisk together sorghum, brown rice, white rice, bicarb soda, and salt in a small bowl. Add to wet ingredients and beat together on low speed.
Use a wooden spoon to mix peanuts and chocolate chunks through the dough.
Chill dough for 30 minutes.
Remove from the oven and roll large tablespoonfuls of dough into spheres and place on lined baking sheets. Leave at least 5cm (2 inches) between balls for spreading.
Bake for 10 minutes, swapping trays halfway through baking time.
Remove from the oven and allow to cool on the tray for 10 minutes before moving to wire rack to cool completely (if you can wait that long).