01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, cinnamon, ginger, nutmeg, baking soda, baking powder, and salt until well blended.
03 - In a large bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy, approximately 2-3 minutes.
04 - Beat in the egg and vanilla extract until fully incorporated into the butter mixture.
05 - Stir the grated carrots into the wet mixture until evenly distributed.
06 - Gradually add the dry ingredients to the wet mixture, mixing by hand or on low speed until just combined. Avoid overmixing.
07 - Gently fold in the rolled oats, nuts, and raisins if using until evenly distributed throughout the dough.
08 - Drop tablespoon-sized mounds of dough onto the prepared baking sheets, spacing approximately 2 inches apart to allow for spreading.
09 - Bake for 11-13 minutes until edges are lightly golden and centers appear set. Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
10 - Beat softened cream cheese and butter together until smooth and creamy. Add powdered sugar, vanilla extract, and salt; continue beating until fluffy and well combined.
11 - Once cookies have cooled completely, spread or pipe the cream cheese frosting onto the flat side of each cookie as desired.