Preheat the oven to 350F and generously grease a 9-inch pan, a bundt pan, or two 6-inch pans. (Tip: Add a square of parchment paper on the bottom for easier removal later.)
To prepare the cake, combine the coconut flour, maple syrup, coconut oil, eggs, cinnamon, ginger, nutmeg, salt, lemon juice and baking soda, and whisk well to create a uniform batter. If any of your ingredients are cold the mixture will be thicker than traditional cake batter, but don't worry, it will still bake just fine! Once the batter is uniform, stir in the shredded carrots, pineapple, and raisins (if using them).
Pour the batter into your prepared pan(s) and bake at 350 until the center is firm, about 40 to 50 minutes. (If using a deep bundt pan, it takes about 50 to 60 minutes.)
Allow the cake to cool in the pan for 20 minutes, then transfer to a wire rack to cool completely before frosting. For best shelf-life, store the cake covered in the fridge for up to one week.
I have tried lowering the number of eggs in this recipe, by replacing 1 egg with 1/4 cup of mashed banana instead. The result is a slightly drier cake that doesn't hold together as well. You can get away with this swap if you need to reduce the recipe by 1 egg, but I don't recommend trying to lower it by much more or the cake won't hold together.
You can also reduce the maple syrup to 3/4 cup if you want a less-sweet cake. I assume honey would work similarly, if that's what you have on hand. (In fact, for honey I wouldn't use more than 3/4 cup because the flavor is stronger than maple syrup.)