Preheat the oven to 375°F (190°C).
Prepare a muffin tin with liners or grease it with non-stick spray.
In a large bowl, combine the flour, sugar, baking powder, and salt.
In another bowl, whisk together the egg, milk, oil, orange juice, and orange zest.
Pour the wet ingredients into the dry ingredients and mix gently until just combined.
Fold in the cranberries carefully.
Spoon the batter into the prepared muffin tin, filling each cup about ¾ full.
Bake for 18–20 minutes or until a toothpick inserted in the center comes out clean.
Allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack.
Serve warm or at room temperature.
