Heat oven to 350ºF. In large bowl, beat brown sugar, egg, oil, applesauce and vanilla on medium speed of electric mixer until combined. Add combined flours, baking soda and salt; beat on low speed just until blended. Stir in oats and “mix-ins.” Drop dough by level measuring tablespoonfuls about 2 inches apart onto ungreased cookie sheets. Bake 9 to 10 minutes, until light brown. (Do not overbake. Centers will appear soft.) Cool 1 to 2 minutes on cookie sheets; transfer to wire racks. Cool completely. Store tightly covered.