Preheat the oven to 160°C. Line a 25cm square cake tin with baking paper and grease with non-stick spray.
1. Cheesecake Mix all the ingredients with an electric whisk until smooth. Set aside.
2. Brownies Put the butter or margarine in a saucepan and heat until melted. Take the saucepan off the heat and add the chocolate. Stir until the chocolate has melted. The chocolate should melt without having to return the saucepan to the heat – if it doesn’t, heat the mixture over very low heat for no more than 5 minutes. Remove from the heat and set aside.