Place the oatbran in a bowl. Sift the flour, baking powder, bicarbonate of soda, cinnamon and ginger over the top and mix together. Add the sugar and stir well.
Mix together in a jug the egg, oil and milk, then pour into the dry ingredients with the cherries and raisins and stir until just mixed. Line a 12-hole muffin tray with 12 paper muffin cases and divide the mixture between them. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 20–25 minutes until well risen and golden. Remove the muffins from the tin and place on a wire rack to cool.
Beat the mascarpone and icing sugar in a bowl, then spoon and swirl on top of each cooled muffin. Decorate each with a cherry and a sprinkling of cinnamon, if liked.