Heat oven to 350ºF. Grease and flour a 9x5-inch loaf pan.
In a large mixing bowl, mash together the bananas, coconut oil, and brown sugar until smooth. Mix in the cajeta, yogurt, and eggs. Add the baking powder, baking soda, and salt and mix well. Gently fold in the flours.
Pour the batter into the prepared pan. Drizzle the remaining 2 tablespoons of syrup evenly over the top; sprinkle with walnuts.
Bake for 50-60 minutes, or until the top of the bread of domed and a toothpick inserted into the center comes out clean.