These moist apple muffins are best served fresh and just warm.
Preheat oven to 200°
In a large bowl combine melted butter, sugar, beaten egg and milk. Sift in flour, baking powder, apple and cinnamon. Stir gently until just combined. The mixture should be lumpy, not smooth.
Spoon mixture into muffin tins until 2/3 full. Combine topping ingredients and sprinkle over muffins. Bake 15-20 minutes until lightly browned.