1. Combine the butter and crushed biscuits until the mixture resembles wet sand. Press into the bottom and up the sides of an 20cm loose-bottomed round tin. Refrigerate for one hour.
2. Meanwhile, beat the cream cheese with an electric whisk until fluffy, then beat in the Irish cream liqueur and icing sugar.
3. Divide the mixture in half, placing one half into a separate mixing bowl. Beat the Nutella into one of the mixtures until combined.
4. Divide the whipped cream between both mixtures and fold in until incorporated.
5. Drop large dollops of each mixture into the base until the tin is full. Gently draw a dull knife through the mixtures to swirl them. 
6. Refrigerate for two hours or until set.
7. Before serving, top with the whipped cream and chopped chocolate hazelnut pieces.

Per Serving 753kcals, 62.7g fat (37g saturated), 38.3g carbs, 24.1g sugars, 9.2g protein, 1.5g fibre, 0.397g sodium