Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat to prevent the cookies from sticking.

In a medium bowl, whisk together the flour, baking soda, cinnamon, ginger, and salt. Set this aside for later.

In a large bowl, use an electric mixer to cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.

Add the egg and vanilla extract to the butter-sugar mixture. Beat until fully incorporated.

Gradually add the dry ingredients to the wet ingredients, mixing until combined. Be careful not to overmix.

Fold in the grated carrots, raisins, and chopped walnuts (if using), making sure the carrots are evenly distributed.

Scoop tablespoon-sized portions of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are golden and the centers are set but still slightly soft. The cookies will firm up as they cool.

Allow the cookies to cool on the baking sheet for about 5 minutes, then transfer them to a wire rack to cool completely.

Prepare the cream cheese frosting: Beat the softened cream cheese and butter together in a bowl until smooth. Gradually add powdered sugar and continue to beat until fluffy. Stir in vanilla extract.

Frost the cookies: Once the cookies have cooled, use a knife or piping bag to spread a small amount of cream cheese frosting on top of each cookie. You can garnish with extra chopped walnuts or a sprinkle of cinnamon.