Preheat your oven to 375°F and line a muffin tin with paper liners or lightly grease it.
In a large bowl, mix the flour, sugar, baking powder, and salt.
In another bowl, whisk together the melted butter, eggs, milk, vanilla extract, and orange juice.
Gradually add the wet ingredients to the dry ingredients, stirring gently until just combined.
Fold in the cranberries and orange zest to distribute them evenly throughout the batter.
Fill each muffin cup about two-thirds full with batter.
Bake for 15-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the tin for a few minutes, then transfer them to a wire rack.