Prepare the crumb topping

1. combine the flour, baking powder and cinnamon in a medium mixing bowl and stir well to mix.
2. Melt the butter in a small pan.Remove from heat and add the brown sugar to the pan of melted butter and stir well.
3. Add the butter mixture to the flour mixture.
4. Set aside in the refrigerator for at least 30 minutes while preparing the muffin batter.

The muffins

1. Preheat the oven to 350 degrees F/180 degrees C.
2. Line 12 muffin cups with paper liners.
3. The dry ingredients – Sift the flour, baking powder, baking soda and salt into the bowl. Add the diced cashew-nuts and stir well.
4. The wet ingredients – Combine the sugar,milk, vanilla, and mashed bananas. Add the melted butter and blend.
5. Add the wet ingredients to the dry ingredients. Scrape the bowl and blend well. Don’t over-mix.
6. Spoon the batter into the paper liners, filling each one to the top.
7. Top each muffin with the crumb topping. Approximately 2 tablespoon each for a muffin.
8. Bake for 25 to 30 minutes, or until the tops are brown and a toothpick comes out clean.
9. Cool slightly, remove from the pan, and serve.