Preheat oven to 170°C. Lightly grease a 20cm square cake pan and line with baking paper, leaving an overhang of 3cm.
Place oats, flour, coconut, cinnamon, baking powder, macadamias, honey and table spread in a mixing bowl, stirring well to combine. Press a third of the mixture into base of prepared pan and bake for 20 minutes.
Place blueberries in a microwave-safe bowl and heat on high for 40 seconds or until just soft. Add cornflour, lightly crushing with a fork to combine.
Spread blueberry mixture over oat mixture to form an even layer. Scatter remaining oat mixture on top and bake slice for a further 25 minutes or until golden. Cool completely in pan before cutting into 16 squares and serving.