Preheat oven to 375 degrees. Prepare three 8 ½ x 4 ½ inch loaf pans. Spray with vegetable spray. Cut a piece of parchment paper to fit the bottom of the loaf pan and lay it in.
In a large mixing bowl, combine 4 eggs and 1 ½ cups sugar. Blend at medium speed for about 5 minutes until thick and light-colored. Add 2 cups overripe bananas, 1 cup buttermilk and 2 tablespoons vanilla and blend until combined.
In a small bowl combine 2 ½ cups all purpose flour, 1 tablespoon + 1 teaspoon baking powder, 1 teaspoon baking soda and 1 teaspoon salt. Stir to distribute ingredients.
Add flour to wet ingredients in three additions, being careful not to over mix the batter.
In the same bowl you used for the flour mixture, combine 1 cup miniature chocolate chips with 1 teaspoon flour and mix with your fingers until chocolate chips are dusted with flour. Stir the chips and 1 cup walnuts into the batter.
Divide the batter evenly between the three prepared loaf pans. Divide ¼ cup miniature chocolate chips and ¼ cup chopped walnuts and sprinkle them over each loaf.
Bake for 35-40 minutes, until golden brown and cake tester comes out clean.
Divide the remaining chocolate chips and walnuts over the top of the three loaves.
Cool on a rack for 20 minutes, then turn out the bread -- removing the parchment paper. Serve.
Notes
Banana bread freezes well. Wrap it in saran wrap, then in freezer paper. Keeps up to two months in the freezer, but if your family knows it's there -- it won't last.