Preheat oven to 180° celsius
Line muffin tin with papers
In a large mixing bowl, combine the flour, spices, sugar and half of the nuts. Make a well in the centre
In a large jug, combine the buttermilk, eggs, vanilla, oil and bananas
Pour wet ingredients into the dry ingredients and fold in, until just combined. Do not overmix!
Using an ice cream scoop, scoop batter into the muffin papers
Sprinkle with remaining walnuts
Bake for 25 minutes, until golden (you can start the glaze while muffins are baking)
Cool in the pan for a few minutes, then transfer to cooling rack and drizzle over glaze