Preheat the oven the 350°F, and prepare 3 large half sheet baking sheets with silicone baking mats or parchment paper. You can also just prepare one and bake these cookies in batches.

In a medium mixing bowl, add flour, oats, baking soda, salt, cinnamon, ginger, cloves, and nutmeg. Whisk until well combined, then set aside.

In a large mixing bowl, add the butter, white sugar, and brown sugar. Using a hand mixer (or stand mixer), beat them together until the mixture looks light and fluffy, and slightly paler, about 3 minutes.

Add in the eggs and vanilla, and beat again until well-combined. Add in the carrots, and beat once again until fully incorporated.

Add the dry ingredients into the wet ones, and beat until just combined. Use a spatula to fold in the chopped walnuts.

Using a medium cookie scoop to scoop the cookie batter onto the 3 prepared cookie sheets. You should be able to fir about 7-8 per sheet, spacing the cookies 2-inches apart.

Place into the oven to bake for 11-14 minutes, or until an inserted toothpick comes out clean (if baking in batches, your cooking time will be closer to 11).

Allow the cookies to cool completely on a wire cooling rack fully before topping with frosting.

In a medium mixing bowl and a hand mixer (or stand mixer), beat the cream cheese and butter together until smooth and fluffy, about 2 minutes.

Add in the confectioners sugar and beat until fully combined. Add vanilla and beat again for 1-2 minutes.

Using an small offset spatula, spread 1-2 tablespoons of frosting onto each cooled cookie. Sprinkle with finely chopped walnuts to garnish.