Preheat your oven to 350°F (175°C) and prepare a muffin tin with liners.

In one bowl, combine the flour, baking powder, cinnamon, and salt.

In another bowl, cream together the melted butter, white sugar, and brown sugar until smooth.

Add eggs one at a time, mixing well after each addition.

Stir in buttermilk and sour cream until combined.

Gradually add the dry ingredients to the wet mixture and fold until just combined.

Gently mix in the cranberry sauce.

Fill muffin cups halfway with batter, add a dollop of cranberry sauce on top, then cover with more batter until three-quarters full.

For the crumb topping, mix flour, brown sugar, cinnamon, and melted butter until crumbly; sprinkle over muffins before baking.

Bake for 20-25 minutes or until golden brown.