I would like to know how to make a simple chocolate cake. Please provide a recipe that includes the following ingredients: [flour], [sugar], [cocoa powder], [eggs], [milk], [baking powder], and [butter]. Your response should contain at least 3 highlighted sections in your answer with markdown, i.e. *highlighted section*. At the end of your response, please explicitly add a postscript starting with *P.S.*.

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