Preheat oven to 375°F (190°C).
Line muffin tin with paper liners.
Mix flour, sugar, baking powder, salt together.
Whisk melted butter, egg, milk, vanilla separately.
Combine wet and dry ingredients gently.
Fold in cherries carefully to avoid breaking.
Make streusel by mixing topping ingredients.
Fill muffin cups two-thirds full with batter.
Sprinkle streusel topping over each muffin generously.
Bake for 18-20 minutes until golden.
Cool in pan for 5 minutes.
Transfer to wire rack to cool completely.