Preheat the oven to 350°F. Lightly grease some cookie sheets.

In a mixing bowl, combine the margarine and sugars, and stir until well blended. Add the egg white and beat well. Mix together the oat bran, rolled oats, baking soda, salt, and cinnamon, add to the margarine mixture, and mix until blended.

Drop by teaspoonfuls onto cookie sheets and flatten with your fingertips (dip your fingers into cold water to prevent stickiness).

Bake for approximately 7 minutes, or until the cookies are just lightly browned. Remove from the oven and let cookies rest on the cookie sheet for about 2 - 3 minutes, until they are easy to remove gently with a spatula. If the cookies become too hard to remove easily, put the cookies back in the oven for about a minute to soften enough to remove. These freeze well; gently stack and place in a plastic bag to store.