Preheat oven to 375ºF (191ºC). Spray a loaf pan (9" x 5") with non-stick spray. Set aside.
Pour the milk into a small saucepan and heat on the stove over medium heat until steaming. Add the oats, remove from heat, and allow to soak for 10 minutes while you prepare the rest of the bread.
In a large bowl, whisk together the flour, Brewer's yeast, flaxseed, baking powder, salt, and cinnamon (if using). Set aside.
In a medium size bowl, whisk together the brown sugar, eggs, vegetable oil, and vanilla until smooth. Add the soaked oats and stir until everything is combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Add the chocolate chips and stir to disperse evenly.
Pour the bread into the prepared loaf pan and bake for 28-30 minutes or until a toothpick inserted in the center comes out mostly clean. You may tent foil over the top of the loaf pan at the beginning of the baking or in the middle to prevent too much browning. Allow bread to cool completely in the loaf pan on a wire cooling rack before serving. Leftovers stay fresh at room temperature up to 4 days or in the refrigerator up to 1 week. Loaf may be frozen, up to 3 months. Wrap tightly in plastic wrap and foil before freezing. Thaw overnight in refrigerator.
*Cinnamon is optional here as it can be an irritant for tiny bellies. If you are sure the baby receiving milk from the consuming mother is not reactive to cinnamon, you may include it. It brings wonderful flavor! Omit it if you are unsure.