Preheat the oven to 350 degrees. Spray a 9x9 inch pan with non-stick spray and line it with parchment paper.
In a medium bowl, whisk together the all purpose flour, cinnamon, nutmeg, ginger, allspice, baking powder, baking soda and salt. Then set aside.
2 1/2 cups (313 g) all-purpose flour, spooned and leveled, 1 tbsp ground cinnamon, 1/2 tsp ground nutmeg, 1/2 tsp ground ginger, 1/2 tsp ground allspice, 1 1/2 tsp baking powder, 1/4 tsp baking soda, 1/2 tsp salt
In a large bowl, cream together the butter, granulated sugar and light brown sugar with an electric mixer on high speed until fluffy, about 3-4 minutes. (If using a stand mixer, use the paddle attachment.) 10 tbsp (140 g) unsalted butter, softened, 1 cup (200 g) granulated white sugar, 1/2 cup (110 g) light brown sugar, packed
Then add in the eggs and vanilla and mix on medium then medium-high speed until smooth, pale in color and slightly fluffy, about 2-3 minutes. Scrape the sides of the bowl with a rubber spatula as needed.
3 eggs, at room temperature, 2 tsp vanilla
Alternate adding the dry ingredients and the buttermilk to the butter mixture a little at a time, until each has been added completely. Mix on low then medium speed just until the batter is combined and smooth, scraping the sides of the bowl as necessary.
3/4 cup (180 ml) buttermilk, at room temperature
Add in the grated carrots and fold them into the batter with a rubber spatula just until combined.
2 cups (220 g) finely grated carrots, at room temperature
Pour the batter into the prepared baking pan.
Bake the cake for 50-54 minutes, or until a toothpick comes out clean from the center of the cake with just a few moist crumbs.
Let the cake cool in the pan for about 30 minutes, then pull up on the parchment paper to release the cake and continue to let it cool on a wire rack until completely cool.