Preheat the oven to 350 degrees F. Lightly grease a 12-cup regular muffin tin with baking spray or butter.
In a large bowl, briefly whisk the flour, sugar, walnuts, salt, and baking soda together. In a separate large bowl, stir together the bananas, eggs, yogurt, brown butter and vanilla. Fold the wet ingredients into the dry, mixing until just combined. Divide the batter evenly between the muffin tins.
Bake until the muffin tops are golden brown, approximately 20-23 minutes. Serve warm or at room temperature.
Notes
You can use regular unsalted butter if you prefer, but brown butter adds a sweet, nutty flavor that's quite lovely. This recipe includes instructions on how to brown butter.Adapted from The Best New Recipe by Cook's Illustrated Magazine