For the mini bundt cakes, preheat the oven to 180°C. Place an 8 mini bundt cake capacity silicone mould on a baking tray. Place the macadamias, flour, sugar and baking powder into the bowl of a food processor and pulse until the mixture becomes a flour-like consistency. Do not over-process or the mixture will start to stick together. Coarse macadamia pieces are ideal. Place the flour mixture into a large bowl.
In a separate bowl, lightly whisk together the eggs, butter, oil and milk. Add to the dry ingredients and stir to combine, taking care not to over-mix. Spoon into the mini bundt moulds so that they are ¾ full. Bake for 10-12 minutes, until puffed and cooked through when tested with a skewer. Cool in the mould for 10 minutes before removing to a wire rack to cool completely.
For the blueberry glaze, combine the blueberries and icing sugar in the bowl of a food processor and process until smooth.
To decorate, generously drizzle blueberry glaze over each bundt cake. Dip the bottom of the edible sugar flowers into the glaze and stick immediately onto a whole macadamia, holding in place for about 30 seconds until the icing sets and the flower stays in place. Place the whole macadamias in the centre of the cake and decorate with little leaves if desired.