Preheat the oven to 200ºC/180°C Fan/400ºF/gas mark 6.Put each crepe in front of you and spread some Nutella over one half, then fold the unspread side over the spread side. Now add a dollop of Nutella over one quarter and fold again, so what you have is a fat, squidgy fan. Place on a buttered swiss-roll tin / jelly roll pan or similar. Proceed with remaining crepes, overlapping them a little in the tin as you go.Put the butter in a small pan with the 80ml / 1/3 cup Frangelico, and heat gently to melt.Pour over the crepes in their tin and sprinkle most of the chopped hazelnuts on top. Bake in the hot oven for 10 minutes.Meanwhile, whisk the cream with the remaining 2 tablespoons Frangelico until you have an aereated soft floppiness, and put into a bowl, sprinkling with the last of the chopped hazelnuts. This luscious cream is a must alongside the sweet, buttery, heavenly crepes.