Step 1

Preheat the oven to 350 F. Use butter or pan spray to generously grease two loaf pans size 8.5" long. (Other sizes work fine but please adjust the baking time.)

Step 2

In a large mixing bowl, whisk together flour, brown sugar, baking soda, baking powder and salt.

Step 3

Puree the butter, bananas, yogurt, eggs and vanilla in a food processor or blender until smooth. (Alternately mash bananas well with a fork and mix well with the rest of the ingredients.)

Step 4

Use a rubber spatula to scrap the contents of the food processor into the flour mixture. Stir everything together just until combined.

Step 5

Scrape the batter into the greased loaf pans.

Step 6

In a medium bowl use a fork or your fingers to mash together the butter, brown sugar, flour and chopped walnuts. Scatter evenly over the bread batter.

Step 7

Bake in preheated oven until the top is a nice golden brown and a cake tester or toothpick comes back with moist crumbs but no wet batter, about 30-35 minutes.

Step 8

Remove from oven and cool 10 minutes. Take bread out of pan and eat warm or cool on a wire rack until bread reaches room temperature and can be wrapped.

Step 9

Bread will store well at room temperature for 3-4 days in Ziploc bag or other air tight container. Each loaf makes 8 large slices.