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 with an electric mixer until creamy and fluffy, about 2 to 3 minutes.
04 - Add the egg and vanilla extract to the butter mixture, beating until well combined and smooth.
05 - Gradually mix the dry ingredients into the wet ingredients, stirring just until combined. Do not overmix.
06 - Gently 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 rounded tablespoons of dough onto prepared baking sheets, spacing about 2 inches apart.
08 - Bake for 11 to 13 minutes, or until edges are golden brown and centers are set. Let cool on the baking sheet for 5 minutes, then transfer 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 piping bag. Allow glaze to set before serving.