Preheat your oven to 350°F (175°C).
Line your muffin tin with parchment liners or lightly grease it with cooking spray.
In a medium mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, cinnamon, and chopped walnuts. Set aside.
In a large mixing bowl, beat the room temperature butter and sugar together until light and fluffy, about 2-3 minutes.
Add the eggs, one at a time, mixing well after each. Stir in the mashed bananas, honey, and vanilla extract until combined.
Gradually add the dry ingredient mixture to the wet ingredients and fold gently until just combined.
Fold in the Greek yogurt or sour cream.
Scoop the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake for 18-22 minutes, or until a toothpick comes out clean. The tops should be golden brown.
Let the muffins cool in the tin for about 5 minutes, then transfer to a wire rack to cool completely.
