01 -
Preheat the oven to 350°F and grease a 9 by 5 inch loaf pan with butter or nonstick spray, dusting with flour to coat.
02 -
In a medium bowl, whisk together the all-purpose flour, baking soda, salt, and ground cinnamon until evenly blended. Set aside.
03 -
In a large mixing bowl, cream the softened unsalted butter with the granulated sugar until pale and fluffy using an electric mixer.
04 -
Beat in the eggs one at a time, fully incorporating after each addition. Blend in mashed bananas, Greek yogurt, and vanilla extract until the batter turns smooth.
05 -
Gradually add the dry ingredient mixture to the wet mixture, folding until just combined. Take care not to overmix.
06 -
Gently fold the fresh blueberries into the batter, ensuring even distribution without crushing the fruit.
07 -
In a small bowl, blend 1/4 cup granulated sugar and 1 1/2 teaspoons ground cinnamon to combine for the swirl.
08 -
Pour half the banana bread batter into the prepared loaf pan. Sprinkle half of the cinnamon sugar mixture evenly over the batter. Add the remaining batter on top, then finish with the rest of the cinnamon sugar. Use a butter knife to swirl through the layers for a marbled effect.
09 -
Place the pan on the center rack and bake at 350°F for 30 to 45 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
10 -
Allow the loaf to cool in the pan for 10 minutes, then transfer to a wire rack to finish cooling before slicing and serving.