Preheat oven to 180C and prepare a 12-cup muffin tray.
In a large bowl, whisk together the flours, collagen, spices, salt and baking powder.
In a medium bowl, whisk together the eggs, almond milk, maple syrup, and mashed banana.
Add the wet ingredients to the dry ingredients and mix until just combined.
Fold in the chopped macadamia nuts.
Distribute the batter evenly into the lined muffin tins, filling each about two-thirds of the way full.
Top with a slice of banana and some macadamia pieces.
Bake for 20 minutes, until a toothpick comes out clean.