Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease well.

In a large bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt.

In a separate medium bowl, whisk together the brown sugar, vegetable oil, eggs, and vanilla extract until combined.

Pour the wet ingredients into the dry ingredients. Mix with a spatula until just combined. Do not overmix.

Fold in the grated carrots, chopped apple, raisins, chopped nuts, and coconut, if using. Mix until the additions are evenly distributed.

Divide the batter evenly among the 12 prepared muffin cups, filling each about two-thirds full.

Bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

Let the muffins cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.