Preheat oven to 375 degrees and fill 2 muffin tins with liners.

In a large bowl, combine the flour, baking soda, and salt; set aside. With an electric mixer fitted with a wire whisk, whip the bananas and sugar together, for a good 3 minutes. Add the melted butter, eggs, and vanilla and beat well, scraping down the sides of the bowl once or twice. Mix in the dry ingredients just until incorporated. Spoon the batter into the muffin tins to fill them about halfway. Sprinkle the tops with walnuts and raw sugar.

Bake until a toothpick stuck in the muffins comes out clean, 18 to 20 minutes. Let cool for a few minutes before turning the muffins out. Serve warm or at room temperature.