Preheat oven to 180°C. Line a 20cm x 30cm lamington pan with baking paper.
In a bowl, combine the muesli, coconut, pepitas, sunflower seeds, sesame seeds and craisins in a large bowl.
Place butter, golden syrup and honey in a heatproof, microwave-safe bowl. Microwave, uncovered, on high for 1 to 2 minutes, or until melted and bubbling.
Pour hot syrup into muesli mixture and corn flour and stir until evenly combined. Spread mixture evenly into the pan and press firmly into all of the corners. It is easier to use a pan that is one size smaller and place pressure down to compact the mixture. Bake for 25 minutes or until crisp and golden. Allow to cool.
Transfer slice onto a chopping board and cut into 16 bars. Drizzle with dark chocolate and allow to set.
