1. Heat the oven to 180C/350F/Gas Mark 4. Grease and line a 22.5x32cm rectangular baking tin with non-stick baking parchment paper.

2. Put the butter, sugar and eggs into a large mixing bowl, sift in the flour, baking powder and ground cinnamon and using an electric mixer, beat the mixture for about a minute to combine. Add the vanilla and milk and beat again for a further minute.

3. Turn the mixture into the prepared tin and level. Squeeze the chocolate toffee over the surface of the cake and using the back of a teaspoon, swirl the chocolate into the cake mixture.

4. Bake the cake for 40-45 minutes until risen and test with a cocktail stick which should come out clean if the cake is cooked. Allow to cool before cutting into portions