Prepare the ramekins by greasing well with extra butter.
Line the base of each ramekin with baking paper cut into a small circle. Place a small amount of cocoa powder into the base of each ramekin and shake it around until the sides are completely covered (the powder will stick to the butter). Shake off any excess cocoa powder and set aside.
Place the plain flour into the TM bowl and press Turbo 5-10 times to sift. Set aside in a separate bowl.
Place the butter and the chocolate into the TM bowl and melt on Speed 3, 60 degrees for 3 minutes (you may need to scrape down the bowl partway through). Pour the chocolate mixture into a separate bowl and set aside.
Place the caster sugar into the TM bowl and mill on Speed 9 for 10 seconds.
Insert the butterfly and add the eggs and additional egg yolks. Mix on Speed 4 for 1 minute.
With the blades still turning on Speed 4, slowly add the plain flour and then the chocolate mixture through the MC hole. Mix until completely combined (about 10 seconds).
Divide the mixture evenly between the prepared ramekins and place into the fridge for at least 30 minutes (up to 24 hours).
Preheat oven to 180 degrees celsius (fan-forced).
Place the ramekins onto a baking tray and place into the oven. Cook for 10-12 minutes or until a slight crust has formed and cakes are beginning to come away from the sides.
Remove from the oven and set aside for 2 minutes. Gently loosen the chocolate cakes from the sides and then place a plate on top of the ramekin and gently flip it over. If you think the chocolate lava cake is not going to come out, gently run a butter knife around the edge of the ramekin before turning out (if the ramekins are well greased and covered in cocoa powder - they should be absolutely fine!).
Remove the baking paper circle and serve with salted caramel popcorn, fresh berries, or ice-cream immediately.