Butter around 25g
Heat butter and chocolate in a bowl which is in hot water.
Keep stirring till they melt.
Remove them from hot water to get cool.
Whip an egg with around 15g sugar till the color becomes light.
Do make sure the chocolate is cool already.
Put around 15g flour into the mixture. Stir evenly. Then put the bowl into fridge for 30 minutes.
Brush butter onto the inner wall of baking bowl.
Put into oven for ten minutes.
Try to scoop it with a small spoon.
And you will be surprised!