01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Simmer apple cider in medium saucepan over medium heat until reduced to 1/2 cup (approximately 10–15 minutes). Allow to cool completely before using.
03 - Whisk together flour, oats, cinnamon, nutmeg, baking soda, and salt in a medium bowl until evenly distributed.
04 - Beat softened butter, granulated sugar, and brown sugar in large bowl until light and fluffy, approximately 2–3 minutes.
05 - Beat in eggs one at a time until fully incorporated. Mix in cooled reduced apple cider and vanilla extract until smooth.
06 - Gradually add dry ingredients to wet mixture, mixing until just combined. Do not overmix.
07 - Gently fold raisins into dough until evenly distributed throughout.
08 - Drop rounded tablespoons of dough onto prepared baking sheets, spacing 2 inches apart to allow for spreading.
09 - Bake for 10–12 minutes until edges are golden brown and centers appear set.
10 - Let cookies cool on baking sheet for 5 minutes, then transfer to wire rack to cool completely.