Position the rack in the center of the oven and preheat to 350 degrees F.

Put the walnuts on a baking sheet and roast until aromatic and lightly browned, 12 to 15 minutes. After 6 to 8 minutes, shake the pan and rotate to ensure even browning. When broken in half, the interior of the walnuts should be golden. Let cool, then roughly chop the walnuts or break them into pieces by hand. Keep the oven set at 350 degrees F.

Spray two 9-by-3-inch loaf pans with vegetable oil cooking spray.

Stir the flour, kosher salt, and cinnamon in a medium bowl. Set aside.

Combine the oil and sugar in the bowl of a stand mixer fitted with the paddle attachment.

Alternatively, use a hand mixer. Beat on low speed, until combined. Add the eggs and vanilla and beat until incorporated about 1 minute.

Stir the baking soda into the buttermilk in a small bowl. Add one-third of the dry ingredients to the mixer, followed by half of the buttermilk, and mix at low speed until it is barely combined 10 to 15 seconds. Repeat. Scrape down the sides and mix in the remaining dry ingredients. Add the mashed bananas and walnuts and mix until just incorporated. (I omitted the nuts) Do not overmix.

Pour the batter into the prepared pans. Bake until the bread is golden brown, and a toothpick inserted into the center comes out clean, about 1 hour. Transfer the pans to wire racks and let cool for 5 minutes, then remove the loaves from the pans and let cool on the racks for at least 10 minutes before serving.