Combine Dry Ingredients. In a medium mixing bowl, combine gluten-free flour, baking powder, baking soda, salt, cinnamon, nutmeg, and cloves. Whisk until evenly blended. Add the chopped pecans and stir to coat well. (This will help prevent them from sinking to the bottom!)
Combine Wet Ingredients. In a large mixing bowl, combine brown sugar, oil, sour cream, eggs, and vanilla. Whisk until smooth. Add carrots and stir to combine. (I find it's easier to blend them in at this point than at the end.)
Add Dry Ingredients To Wet Ingredients and stir to combine.
Let Batter Rest 1 Hour. Then let the batter rest at room temperature 1 hour. This will give the flour time to hydrate and makes a HUGE difference in the rise of the muffins. (They'll rise 1/2-3/4 of an inch taller if you let the batter rest!)
Preheat & Prep. While the batter rests, preheat the oven temperature to 425 degrees F. Line a 12-cup metal muffin pan with parchment paper liners.
Bake & Cool. Scoop batter into muffin cups, filling about 90% of the way full (keep in mind you'll have better left for about 4 more muffins!) Sprinkle with coarse sugar and bake 5 minutes at 425 degrees. Leave the muffins in the oven and lower temperature to 350 degrees F and continue baking 12-15 minutes or until muffins are cooked through. Let muffins cool 1-2 minutes in the muffin pan before transferring to a wire rack to finish cooling completely. Repeat with remaining muffin batter.
Serve & Store. Enjoy muffins when cooled. Store leftover muffins in an airtight container 2-3 days at room temperature, 3-4 days in the refrigerator, or up to 2 months in a freezer-safe bag in the freezer.