To make Banana Muffins with Choco Swirls, start by preheating the oven at 175°C.
Prepare a 12 cup muffin tray by lining with paper cups. If you don't have paper cups, grease and flour the cups.
In a large bowl, mix the dry ingredients - flours, baking powder, baking soda, salt.
Mash the bananas with a fork or the back of a wooden ladle. Mash in the sugar, oil, vanilla extract. Beat in the egg.
Make a well in the dry ingredients and add the wet ingredients. Mix gently until just combined.
Remove roughly 1/2 cup of batter in a small bowl.
Add the chocochips (and any nuts if using) to the remaining batter. Stir through and distribute between the 12 muffin cups.
To the remaining 1/2 cup batter, add 2 tsp cocoa powder, and thin using 2-3 tbsp of club soda. If you don't happen to have soda on hand, then just use milk instead.
Add a spoonful this cocoa-batter on top of each muffin and give it a swirl with a toothpick.
Keep inside preheated oven to bake for 15 minutes or until a skewer comes out clean.
Serve warm.
These will stay in an airtight container in the refrigerator for 3-4 days. Warm in microwave for 10 seconds before serving.