– 1 1/4 cups 150 g walnuts, coarsely chopped – 2 cups 240 g all-purpose flour – 1 cup 200 g brown sugar – 3/4 teaspoon baking soda – 1/2 teaspoon salt – 3 1 1/2 cups or 450 g large overripe bananas, mashed – 1/4 cup 4 tablespoons plain whole fat yogurt – 2 large eggs beaten lightly – 6 tablespoons unsalted butter melted, plus more for greasing – 1 teaspoon vanilla extract – 2 tablespoons rum