01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium mixing bowl, whisk together the rolled oats, flour, baking soda, cinnamon, and salt until well blended.
03 - In a large bowl, beat the softened butter, light brown sugar, and granulated sugar with an electric mixer on medium speed until light and fluffy, about 2 minutes.
04 - Add the egg and vanilla extract to the creamed mixture and beat until fully combined.
05 - Gradually add the dry ingredients to the wet mixture, mixing on low speed or by hand until just incorporated; do not overmix.
06 - Using a spatula, gently fold in the diced apple, chopped dates, and raisins until evenly distributed throughout the dough.
07 - Scoop tablespoon-sized portions of dough and arrange them 2 inches apart onto the prepared baking sheets.
08 - Bake for 12 to 14 minutes, or until the cookie edges are golden and the centers appear set.
09 - Allow cookies to cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.