Heat oven to 375°F (218°C). Grab a 12-cup muffin tin and grease with oil or cooking spray.
In a medium bowl, mix together the dry ingredients: flour, spices, baking powder, baking soda, salt, and nutmeg. Set aside.
In a large bowl or stand mixer, whisk together the wet ingredients: yogurt, oil, honey, eggs, and vanilla. Then mix in the grated carrots.
Add the dry ingredients to the wet and mix until just combined. Gently stir in the nuts, if using.
Divide the batter evenly among the muffin cups. Bake for about 20-25 minutes, or until a toothpick or cake tester comes out clean.
Let muffins sit for 5 minutes, then transer to an iron rack for cooling. Can store muffins at room temp for 1-2 days, then store in fridge or freezer.