Preheat the oven to 350℉ and toast the walnuts for 5- 10 minutes, shaking the pan occasionally. Be sure not to burn them. Remove to a bowl or plate to cool.
Coat a loaf pan with Baker's Joy, or spray with oil and dust with flour.
In a large bowl, sift together the flour, sugar, baking soda, and salt. Add the cooled walnuts and whisk to combine. Set aside.
In a medium bowl, mash up your bananas with a fork or potato masher. Add yogurt, eggs, and vanilla. With a fork, whisk up the eggs in the mixture.
Add the melted and cooled butter to the rest of the wet ingredients and mix with a wooden spoon until well combined.
Make a well in the middle of the dry ingredients. Pour the banana mixture into the well and use a rubber spatula to gently combine the dry and wet ingredients. Mix just until there are no streaks of flour. The batter will be chunky.
Pour the batter into the prepared loaf pan and use the spatula to evenly spread the mixture into all four corners.
Bake for 60- 70 minutes. After 45 minutes, tent a piece of foil over the bread. After the loaf is done baking, use a cake tester to check the the middle of the loaf is cooked through. Or check that the internal temperature is 190°F- 200°F
Cool in the pan for 15- 30 minutes before turning out onto a cooling rack. Make sure to cool completely before slicing.