• Preheat oven to 425°F and line muffin tin with liners.
• In a bowl, blend together the flour, cinnamon, nutmeg, baking soda, and baking powder.
• In a large bowl, blend eggs, sugar, oil and vanilla extract.
• Add in the mashed bananas and blueberries. 
• Slowly add the dry ingredients into the wet ingredients until blended well.
• Fill the muffin liners all the way to the top.

Crumb Topping*

• Combine the melted butter, flour, granulated sugar, brown sugar, salt, and cinnamon until crumbly.
• Divide the crumb topping evenly among the 12 muffins and press in gently.
• Top the crumb topping with blueberries.
• Bake in the oven at 425° for 5 minutes and then reduce the oven temperature to 350° for 12 additional minutes.
• Remove from oven and allow to cool completely before drizzling with glaze.

Sweet Vanilla Glaze

• In a small bowl, combine confectioner's sugar, vanilla extract, and milk until smooth.
• Drizzle on top of cool muffins.