Preheat and Prep: Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans and dust with flour (or line bottoms with parchment paper).

Whisk Dry Ingredients: In a medium mixing bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, ginger, and nutmeg.

Mix Wet Ingredients: In a large bowl, whisk together the vegetable oil, granulated sugar, and brown sugar until smooth. Beat in the eggs one at a time, followed by the vanilla extract.

Combine and Add Carrots: Gradually stir the dry flour mixture into the wet mixture. Mix just until combined—do not overmix. Switch to a spatula and gently fold in the grated carrots until evenly distributed.

Bake the Layers: Divide the batter evenly between the prepared pans. Bake for 35 to 45 minutes, until a toothpick inserted into the center comes out clean. Check at 35 minutes; if browning too fast, tent loosely with foil.

Cool Completely: Cool in pans for 10 minutes, then invert onto a wire rack to cool completely. Do not frost warm cakes!

Make the Frosting: In a large bowl, beat the softened cream cheese and butter on medium-high speed for 2-3 minutes until completely smooth and lump-free. Reduce speed to low and gradually add 3 cups of sifted powdered sugar, vanilla, and salt. Beat on high for 3 minutes until fluffy. (Add the remaining 1 cup sugar if a stiffer consistency is desired).

Assemble and Frost: Spread a thick layer of frosting over the first cake layer. Top with the second layer. Use the remaining frosting to cover the top and sides, using the back of a spoon to create deep swoops. Refrigerate for 30 minutes before slicing.