Preheat oven to 375°F and grease or line a mini muffin tin. Make the flax eggs by stirring together the ground flax and water. Let sit for about 5 minutes to thicken.
In a large bowl, whisk together the dry ingredients: whole wheat flour, baking powder, cinnamon, nutmeg, salt, and hemp hearts.
In a separate bowl, combine the wet ingredients: Greek yogurt, mashed banana, flax eggs, maple syrup, and avocado oil.
Add the wet ingredients to the dry and stir until just combined. Fold in the shredded carrots and raisins. The batter will be on the drier, stickier side. Add a splash of water if it needs a little more moisture.
Divide the batter evenly among the mini muffin cups and sprinkle the tops with a little sugar, if desired. Bake for 12–15 minutes, or until a toothpick inserted in the center comes out clean. Cool for 5–10 minutes before removing from the pan.