Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan thoroughly.

In a medium bowl, whisk together flour, baking soda, and salt. Set aside.

In a large mixing bowl, cream together softened butter and brown sugar until light and fluffy.

Add in eggs, one at a time, mixing well after each addition. Stir in yogurt and vanilla extract.

Mash the ripe bananas and mix into the wet batter until fully incorporated.

Gradually fold the dry ingredients into the banana mixture until just combined.

Combine granulated sugar and ground cinnamon in a small bowl.

Pour half of the banana batter into the loaf pan, sprinkle half of the cinnamon-sugar mixture on top, then layer with remaining batter and cinnamon-sugar.

Using a knife or skewer, gently swirl the batter and cinnamon-sugar together.

Bake in the preheated oven for 60-65 minutes. Check doneness with a toothpick.

Allow the bread to cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.