Step 1

Preheat the oven to 180°C/350°F and line muffin pans with cupcake liners.

Step 2

Whisk the flour, rolled oats, baking powder, salt and cinnamon together in a large mixing bowl.

Step 3

In a separate bowl, whisk together the bananas, eggs, brown sugar, vanilla and oil.

Step 4

Pour the wet ingredients into the dry ingredients and mix until just combined.

Step 5

Fold in the walnuts and seeds.

Step 6

Transfer the batter to the prepared pans, filling each muffin cup.

Step 7

Top the batter with a few teaspoons of crumble mixture.

Step 8

Place the muffins pans in the preheated oven and allow to bake for 20-25 minutes until golden brown and a toothpick inserted comes out clean.

Step 9

Remove from the oven and allow to cool completely before serving.