Preheat oven to 350°, prepare a loaf pan by lining with parchment paper.
In a medium-size bowl whisk together egg, olive oil, honey, almond milk, and vanilla.
In a large bowl combine oat flour, cinnamon, baking powder, baking soda, and salt. Whisk together to combine.
Add wet ingredients into dry ingredients and stir well to combine. Fold in walnuts, zucchini, rhubarb, and chia seeds. Do not over mix, oat flour will become quite gummy if over mixed.
Pour batter into a loaf pan lined with parchment paper.
Bake at 350° for 40-45 minutes. Or until a toothpick inserted into the center comes out clean. The top of the bread should be slightly brown.
Allow to cool completely. Slice and serve.
Storage - Freezer friendly! Store in freezer in glass lock container, or wrapped in foil for up to 5 months or in the refrigerator for 1 week.
You can easily make your own oat flour by blending rolled oats in a high speed blender until it resembles flour.