Preheat the oven to 375°F. Lightly grease (or line with parchment) two or more baking sheets., Beat together the butter and sugars, then beat in the eggs and vanilla., Grind the oats in a blender or food processor until they've turned to a coarse powder; add to the sugar mixture along with the flour, baking powder, baking soda, salt, chips, and fruit or nuts. Beat gently until well combined., Drop the dough by tablespoonfuls onto the prepared baking sheets; a tablespoon cookie scoop works well here. Leave about 1 1/2" between each ball of dough; the cookies will spread., Bake the cookies for 14 to 15 minutes, or until they're very lightly browned. Remove them from the oven, and cool right on the pans. If you need the pans for the next batch, transfer the cookies to a rack to cool.