Whisk together the flour, sugar, baking soda, baking powder, salt and spices in a large bowl. Add the oil and eggs and whisk or stir until you have a smooth batter. Using a rubber spatula, fold in the carrots until just blended. They will release their juices as you stir, easing the process. Divide the batter between the two cake pans. Bake until the surfaces of the cakes are deeply golden and a toothpick inserted into the center comes out clean, around 30-35 minutes (the original recipe calls for 25 minutes, although I have found this to be too short – with so many carrots in it, the cake has never dried out on me). Allow the cakes to cool on racks and then, in the case of the round cakes, remove from the pans. The sheet cake can be frosted directly in the pan once it has cooled completely.