Melt butter and chocolate in a pan over gentle heat. Stir to combine then allow to cool a little.
Place sugar into a mixing bowl then sift in the dry ingredients. Make a well in the centre and break in the eggs. Pour in the butter mixture.
Stir from the inside out until just combined. Stir in the marmalade.
Divide the mixture between 24 silicone mini muffin moulds.
Place a shred of marmalade on top of each one.
Bake at 180℃ for 15 minutes or until the cakes are well risen and firm to the touch.
Turn out onto a wire rack to cool.
Makes 24 mini cakes or 12 regular bun sized ones.Please note: calories and other nutritional information are per serving. They're approximate and will depend on serving size and exact ingredients used.