1. Whizz the fl our, cocoa, eggs, milk and butter in a blender with a pinch of salt. Transfer to a jug and chill for 1 hour.
2. To make the chocolate spread, blitz the hazelnuts in a food processor with half the sugar until fi nely ground; set aside. Put the cream and remaining sugar in a pan and heat gently to dissolve the sugar. Bring just to the boil, then remove from the heat; add the chocolate and nuts. Leave to stand for 1 minute, then stir until smooth.
3. Heat a 20cm non-stick frying pan over a medium heat and brush with melted butter. Pour in a small ladle of batter and tip the pan so it spreads evenly (add a splash more milk if the mixture is too thick). Cook for 1 minute, then flip over using a spatula; cook for a few seconds on the other side. Keep warm while you cook the rest, adding more butter to the pan each time. Spread with the chocolate spread, fold and serve.