Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners.

In a medium bowl, whisk together flour, baking powder, salt, and both sugars.

In a separate bowl, combine melted butter, milk, egg, and orange zest. Mix well.

Pour the wet ingredients into the dry ingredients and gently fold in the cranberries.

In a small bowl, prepare the streusel topping by combining flour, brown sugar, and butter until crumbly.

Scoop the muffin batter into the prepared muffin tin, filling each cup about two-thirds full.

Sprinkle the streusel topping generously over each muffin.

Bake for 18-20 minutes or until muffins are golden brown and a toothpick comes out clean.

Remove from the oven and allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack.