Serves: 20 truffles1) Preheat the oven to 150°C/Gas mark 3. Chop the hazelnuts, place them on a sheet pan and roast in the oven for 10 minutes (if the hazelnuts have skin on them, roast them for 25 minutes). Set aside to cool.
2) Chop the chocolate finely and place in a bowl. Heat the cream in a small saucepan until it boils. Immediately pour the hot cream through a fine-meshed sieve into the bowl with the chocolate.
3) With a wire whisk, slowly stir the cream and chocolate together until the chocolate is completely melted (if the chocolate doesn't melt completely, place the bowl over a pan of simmering water and stir for a few minutes just until it melts).
4) Whisk in the hazelnut liqueur, coffee and vanilla. Cover and chill for 45 minutes to 1 hour until fairly firm but still pliable enough to scoop.
5) With 2 teaspoons or a 3cm ice cream scoop, make dollops of chocolate mixture on a baking sheet lined with greaseproof paper. Refrigerate for about 15 minutes, until firm enough to roll into rough spheres.
6) Roll the chocolate in the chopped hazelnuts and chill again. Truffles are best when they're allowed to set overnight in the refrigerator.