30 Petit Beurre Biscuits. Custard cook accordingly to packet instruction with 1 or 2 tablespoons of cocoa powder. Dip biscuit one at a time in milk.Spread some custard evenly on each biscuits and line them up with custard in between.
Melt 150g milk chocolate and 60g butter in microwave for 1 minutes. Pour chocolate mixture over cake and sides. Sprinkle with chopped toasted hazelnuts. Refrigerate for at least 2 hours.Cut into diagonal and serve.