Preheat oven to 350°F. Prepare a 12-cup muffin pan with nonstick spray or muffin liners.
In a large bowl, gently whisk flour, baking soda, baking powder, cinnamon, and salt. Add cranberries to flour mixture. Toss to evenly coat.
In a separate medium bowl, whisk together grated carrots, brown sugar, buttermilk, oil, eggs, and orange zest.
Add liquid ingredients to flour mixture. Using a spatula, fold ingredients until just moistened. Do not overmix.
Use a ¼ cup portion scoop to divide out the batter. Cook for 18-20 minutes, or until a toothpick inserted comes out clean. Enjoy!