01 - Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease.
02 - Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl.
03 - Beat eggs, then whisk in vegetable oil, buttermilk, orange zest, orange juice, and vanilla until smooth.
04 - Pour wet ingredients into dry mixture and gently fold with a spatula until just combined; avoid overmixing.
05 - Evenly fold cranberries into the batter.
06 - Divide batter evenly into prepared muffin cups and optionally sprinkle tops with coarse sugar.
07 - Bake for 18 to 22 minutes until a toothpick inserted into the center comes out clean.
08 - Allow muffins to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.