Chocolate Biscuit Cake

My sister-in-law Alwyn introduced me to this magical cake during one of our trips to Ireland.  It is a very simple, no-bake cake which is a beautiful mixture of biscuits, butter and chocolate. I can't seem to find the same tea biscuits that I love in Ireland at my local grocery stores so I have substituted graham crackers (plain) and it seems to produce a similar flavor.  You may be shocked at the holy-jesus amount of butter that is in this recipe but just try to forget about it and enjoy.  I double this recipe when I make it because it makes 8-10 nice chunky pieces and using just 1x the ingredients seemed to not be enough to fill my pan up.

150g (5 oz) plain chocolate, chopped (dark, milk or a combo. I personally think all milk chocolate makes it a bit too sweet so I like to use all dark or a combo)
150g (5oz) butter
2 large tbsp light corn syrup
225g (8 oz) semi-sweet biscuits, such as digestives, crushed
25g (1 oz) hazelnuts or almonds, chopped and toasted (optional)

Melt the chocolate with the butter and corn syrup in a large bowl sitting over a saucepan of simmering water on low heat. 

Stir in th crushed biscuits and nuts (if using) until well blended.  Spread into a 9 " round or 8" square baking pan, lined with parchment paper.

Refrigerate for a couple of hours until well set, or pop into the freezer for 45 minutes.  Cut into squares.

Note: This recipe is from a Rachel Allen cookbook.