Melt the butter in a small heavy-based saucepan over medium heat. Add the sugar, cream, whiskey and salt and stir to combine. Bring to a very gentle boil and cook for 10-15 minutes, stirring occasionally.
Roast the walnuts in the oven until nicely browned but not burnt! Fold the warm chocolate pancakes into triangles and place a scoop of vanilla icecream inside each one. Serve 2 pancakes per person, drizzled with lots of butterscotch sauce and sprinkled with walnuts.
Serves 6