250g packet plain sweet biscuits
125g butter, melted
1/4 cup chocolate chips
1/2 tsp cinnamon
2 tsp cocoa750g dark chocolate
250g butter
3/4 cup caster sugar
4 eggs

1. Place biscuits in a food processor and process until finely crumbed.

2. Mix together melted butter and chocolate chips, then combine with biscuit crumbs, cinnamon and cocoa.

3. Press crumb mixture into the base and sides of a 23cm springform cake pan. Refrigerate until cold and firm.

4. Gently melt the chocolate, either in a microwave or a double boiler, or in a heatproof bowl over a saucepan of just-simmering water.

5. Mix together the butter and sugar until white and fluffy. Whisk eggs, then add to butter and sugar.

6. Pour chocolate into butter mixture and mix well. Pour chocolate filling into the base and the smooth the surface.

7. Chill cake in the refrigerator for 1 1/2 hours. Cut into thin slices with a hot knife before serving.