Pre-heat the oven to 425°F.
Prepare a 12-cup muffin pan with paper baking cups or spray with non-stick cooking spray.
In a large bowl, whisk together flour, brown sugar, poppy seeds, baking powder, baking soda and salt.
Stir in the eggs, olive oil and orange zest without over-mixing.
Fold in shredded carrots and buttermilk.
Evenly spoon the batter into the muffin pan cups, filling two-thirds full.
Place in the pre-heated oven and bake for 5 minutes at 425°F.
After the 5 minutes, without opening the oven, reduce heat to 350°F.
Continue baking muffins for about 12 to 14 more minutes or until golden brown and toothpick inserted comes out clean.
Remove from the oven, place on a wire rack and allow them to cool completely.