Combine the vegetable oil and light brown sugar and four eggs in a large glass mixing bowl. Use a wire whisk to beat the mixture on medium speed for exactly 2 minutes until the sugar dissolves and the liquid turns a pale caramel color. You'll see the oil and eggs fully emulsify into a smooth glossy ribbons. (I used to just stir this by hand but the whisking adds necessary air that makes the crumb lighter). Beat the mixture at a medium pace - this builds the structural base that holds up the heavy carrots later.

Sift the all-purpose flour and cinnamon and baking soda directly over the wet mixture. Use a large rubber spatula to fold the dry ingredients in using a J-shaped motion from the bottom to the top. Work the batter for about 45 seconds until you no longer see white streaks of flour. The batter will become thick and fragrant with spices. Stop folding the second the flour disappears - overmixing at this stage develops too much gluten and makes the cake tough.

Dump the 3 cups of freshly grated carrots and 1 cup of chopped toasted pecans into the bowl. Fold them gently for 30 seconds until they're evenly distributed through the thick batter. You'll see the orange carrot shreds and brown pecan pieces poking through the dark batter. (I tried using pre-shredded carrots once but they were too dry - the fresh ones release juice that makes the cake moist). Fold the heavy inclusions in by hand - using a mixer now would crush the pecans and ruin the texture.

Pour the batter into a greased 9-inch round cake pan and smooth the top with your spatula. Bake at 350°F for exactly 35 to 40 minutes until a toothpick inserted in the center comes out clean. The top will turn a deep golden brown and the edges will pull away slightly from the pan. You'll smell the cinnamon and toasted nuts filling the whole kitchen. Bake at exactly 350°F not higher - the sugar in this batter burns easily if the oven is too hot.

Whip the softened cream cheese and maple syrup until fluffy then spread it over the cooled cake. Use an offset spatula to create thick swirls and peaks across the top and sides. The white frosting should look thick and creamy against the dark spiced cake layers. Scatter extra chopped pecans over the top in an uneven pattern for a homemade look. Wait until the cake is completely cold before frosting - otherwise the cream cheese will melt into a messy puddle.