01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the flour, oats, cinnamon, baking soda, and salt until evenly distributed.
03 - In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar together until light and fluffy, about 2 to 3 minutes.
04 - Blend in the maple syrup, eggs, and vanilla extract, beating until the mixture is smooth and well combined.
05 - Gradually add the dry ingredient mixture to the wet ingredients, stirring until just combined. Do not overmix.
06 - Gently fold in the diced apple, raisins, and chopped nuts if using, distributing them evenly throughout the dough.
07 - Drop rounded tablespoonfuls of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
08 - Bake for 11 to 13 minutes, rotating the sheets halfway through, until the edges are golden brown and the centers appear set.
09 - Let the cookies rest on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely before serving or storing.