Preheat the oven to 350 F, grease and flour a muffin pan.
In a large bowl cream together the butter, sugar and zest until light and fluffy. Add in the eggs and cream again until fully mixed. Sift in the flour and baking powder and stir in until just combined. Spoon the batter into the prepared pan and smooth out. Bake for 20-25 minutes until the cakes are golden brown and a toothpick inserted into the centre of a cake comes out clean. Turn the cakes out onto a wire rack.
In a small bowl, stir together the syrup ingredients (lime juice, cordial and water). Poke holes all over the cakes and brush with the syrup then leave to cool completely.
In another small bowl place the powdered sugar. Add elderflower cordial, a teaspoon at a time, stirring between additions until a thick glaze mixture is formed. Spoon this over the cakes then decorate with mango cubes, candied zest and elderflowers before the glaze sets. Leave to set and then serve, storing leftovers in an airtight container for up to 3 days.