Preheat the oven to 325°F. Lightly oil a 9" cake pan with coconut oil. Use a circular parchment paper liner on the bottom of the pan to further prevent sticking.
In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, salt, cinnamon, and nutmeg.
Add the avocado oil, eggs, shredded carrot, and pineapple. Stir until everything is thoroughly combined. The batter will seem thicker than traditional cake batter, more like a very thick muffin batter. But it should not seem dry.
Transfer the batter into the cake pan. Make sure it is spread out into an even layer.
Bake for 40-45 minutes. A toothpick inserted into the center of the cake should come out clean and the cake should bounce back when gently pressed.
Remove the cake from the oven an allow it to cool for 10-15 minutes. Then remove the cake from the cake pan and allow it to cool completely before frosting and decorating. The cake will deflate some as it cools, but that is normal.