Preheat oven to 180C (400F) degrees fan-forced and line a 12-cup standard muffin tin with paper liners.
In a large bowl stir together the flour oats, brown sugar, cinnamon, baking powder, baking soda and salt.
In another bowl, whisk together melted coconut oil, yogurt, egg and vanilla.
Pour the wet ingredients into the dry ingredients and use a spatula to fold it all together until just combined.
Fold through the zest, blueberries and passionfruit.
Divide the batter between the muffin liners.
Bake for 15-18 minutes, or until a tester inserted in the middle comes out clean.
Remove from oven and cool on a wire rack.