Preheat your oven to 350°F (177°C) and grease a 9x5-inch metal loaf pan.

In a medium mixing bowl, whisk together flour, baking soda, cinnamon, and salt.

Cream together softened butter and sugar until smooth; incorporate eggs one at a time.

Add mashed bananas, yogurt, and vanilla extract to the butter mixture and mix until combined.

Gradually fold in the dry mixture to the wet batter until just combined.

In a small bowl, combine granulated sugar and ground cinnamon for the swirl mixture.

Pour half of the batter into the loaf pan, sprinkle half of the cinnamon-sugar mixture, then add the remaining batter and the rest of the cinnamon-sugar mix, swirling with a knife.

Bake for 55-65 minutes; check doneness with a toothpick.

Cool in the pan for about 1 hour, then transfer to a wire rack.

Whisk together confectioners’ sugar and cream or milk until smooth for the icing.

Drizzle the icing over the cooled bread and serve.