01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger until well blended.
03 - In a large bowl, beat butter, granulated sugar, and brown sugar until creamy and fluffy, approximately 2–3 minutes.
04 - Add the egg and vanilla extract to the butter mixture, mixing until fully incorporated.
05 - Gradually mix dry ingredients into the wet ingredients until just combined, being careful not to overmix.
06 - Fold in grated carrots, oats, walnuts or pecans if using, and raisins if using until evenly distributed.
07 - Using a tablespoon or small cookie scoop, drop dough onto prepared baking sheets, spacing approximately 2 inches apart.
08 - Bake for 11–13 minutes, or until edges are golden brown and centers are set. Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
09 - Beat cream cheese, powdered sugar, milk, and vanilla extract together until smooth and creamy. Drizzle over cooled cookies using a spoon or small piping bag. Allow glaze to set before serving.