Heat a griddle pan to high. Cook the bananas for 2-3 mins each side until charred.
Meanwhile, remove the lids from the custard and push the chocolate into each. Microwave each pot on High for 1 min. Remove and leave to stand for 1 min, then stir well. Divide the custard between 2 bowls, add the hot bananas and sprinkle each with hazelnuts.