Banana Bread Doughnuts

1. Preheat oven to 325 degrees. Lightly coat the doughnut pan with cooking spray and set aside. Note: If you don't have a doughnut pan, you can either make these "doughnut muffins," or pour the batter into a bundt pan for one giant doughnut!
2. In a large bowl, whisk together flour, baking soda, and salt. Set aside.
3. In a medium bowl, combine coconut oil, mashed bananas, agave syrup, yogurt, egg, and vanilla, and whisk until smooth.
4. Add the wet mixture to the dry mixture, and stir until just combined.
5. Now it's time to fill the pan: Pour the batter into a resealable plastic bag (or a pastry bag). Cut off one corner of the bag, and squeeze batter into the prepared doughnut pan, making sure each indentation is about 3/4 full.
6. Top with walnuts pieces, and lightly press them into the batter.
7. Bake for 14 to 16 minutes, or until the doughnuts are golden and spring back when touched. Remove from the oven and cool in the pan for a few minutes, then carefully turn out into a wire rack and cool fully. (Note: Baking time will vary if using a different type of pan.)