Prepare your flax eggs by mixing together 2 tablespoons ground flaxseed with 5-6 tablespoons water. Set aside for 5-10 minutes or until gelatinous.
In a stand mixer with spatula attachment or a large bowl with a hand mixer, cream together the room temperature butter, brown sugar, and mashed banana, about 2 minutes.
Next beat in the flax eggs, vanilla extract, and blackstrap molasses, about 1 minute.
Slowly mix in the baking soda, cinnamon and then flour until just combined.
Finally, slowly mix in the oats and raisins. This dough will be thick and sticky.
Chill the dough in the refrigerator for no more than 30 minutes. If you chill for longer, allow to sit out on the counter for 10-15 minutes before baking or the cookies will not spread.
While the dough chills, preheat oven to 350 degrees, Fahrenheit.
Roll cookie dough into 3 tablespoon sized balls and space out onto two baking sheets. I recommend using a cookie scoop for this and lightly oiling your hands so the batter does not stick to you. Once rolled into balls, lightly press the cookies down into rounds or they will not spread much on their own. You should have about 24 cookies.
Bake for 10-12 minutes. You want the cookies to be slightly underbred so they are soft and chewy.
After baking, allow cookies to cool and set for 5 minutes, then transfer cookies to a cooling rack.
Store cookies at room temperature for up to 7 days.
Notes
You can taste the banana in these cookies when warm. The banana flavor is much more mild when cooled, however, if you want a more neutral tasting cookie, swap mashed banana for 1/2 cup pumpkin puree or 1/2 cup apple sauce.
Swap the raisins for vegan chocolate chips for an oatmeal chocolate chip cookie.