9–12 tsp chocolate hazelnut spread, such as Nutella
100g/3½oz caster sugar
handful toasted hazelnuts, roughly chopped
50g/1¾oz icing sugar
½ tsp flaky sea salt
2 tbsp chocolate curls
100g/3½oz unsalted butter, melted
7 large sheets filo pastry
200g/7oz mascarpone
150g/5½oz ricotta