Preheat the oven to 200^oc/ Gas 6.
Start by making the sauce: put the muscovado sugar, butter, cream, and salt into a small saucepan and place over a medium heat. Stir well and bring to a gentle simmer, then cook for 1 minute. Leave to cool for 1 minute.
Place the chocolate chips in a small heatproof bowl and pour the caramel over them. Stir until the chocolate has melted and the sauce is well combined, then leave to cool.
Put the nuts on a baking tray and place in the over for 5 minutes, or until lightly toasted. Allow to cool before roughly chopping them.
Sprinkle the caster sugar over the cut side of the bananas, then run a blowtorch over each one to caramelise it well. Alternatively, place the bananas, sugar side up, under a hot grill for 5 minutes, or until caramelised.
Place two halves of banana on each serving plate, then put two scoops of ice cream in the middle. Drizzle the caramel sauce over the top and sprinkle with the toasted nuts before serving.

Banana Split with Salted Caramel Chocolate Sauce