Preheat your oven to 350 degrees. Grease a standard muffin tin or fill with cupcake liners and set aside.

In a large bowl, whisk together the flour, sugar, baking powder, baking soda, salt, cinnamon, and nutmeg.

In a medium bowl, mix together the Greek yogurt, eggs, melted butter, 1 teaspoon vanilla extract, and mashed bananas.

Make a well in the flour mixture. Pour in the banana mixture and fold until just combined. Mix in the blueberries.

Fill each muffin cup until completely full (not 3/4 full or you won't get a good muffin top).

Place in the oven with a cookie sheet underneath to catch any drips.

Bake for 40 minutes, or until a toothpick inserted in the center of a muffin comes out clean.

Allow the muffins to fully cool.

To make the glaze: whisk together the powdered sugar, milk, and remaining 1 teaspoon vanilla extract until a glaze is formed. Add additional milk, if needed.

Refrigerate the vanilla glaze until ready to use and remix prior to glazing the muffins.