Preheat the oven to 350°F. Butter and flour a 9x5 loaf pan.

In the large bowl of an electric mixer beat the butter and sugar until smooth and creamy. Beat in the eggs and vanilla and mix until fully combined. Add the bananas one at a time, beating well after each addition.

In a separate bowl, mix 2 cups of flour, baking soda, nutmeg, and cinnamon. Turn the mixer on low and add the dry ingredients slowly, mixing until just combined.

Toss the blueberries with the remaining flour and stir them carefully into the batter with a spatula.

Spread the batter into the prepared loaf pan and bake for 50 minutes to 1 hour, or until the center is set and a cake tester inserted into the center comes out clean.

Allow it to cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.