Preheat oven to 210°C. Melt orange marmalade and butter in a non-stick pan. Sift refined flour, baking powder, baking soda and powdered sugar into a bowl. Make a well in the centre and break the egg into it. Add a little milk and mix till smooth. Add rest of the milk and mix well. Add the melted marmalade-butter mixture and mix well. Add 1 tbsp black sesame seeds and mix.
Pour the batter into silicone muffin moulds till ¾ full. Arrange them on a baking tray. Sprinkle some black sesame seeds on top and bake in the preheated oven for 12 minutes. Cool slightly, demould and serve.