Preheat oven to 425°F. Line a standard 12-cup muffin tin with paper liners and spritz with nonstick spray. Set aside.
In a medium bowl, whisk together flour, baking powder, salt, cinnamon, nutmeg, ginger and cloves. Set aside.
In a large bowl, use an electric mixer on medium-high speed to cream together the butter and sugar until light and fluffy, about 2-3 minutes. Add the eggs, one at a time, mixing well after each addition. Mix in the vanilla extract.
Add half of the flour mixture to the bowl; mix on medium-low speed just until combined. Add the buttermilk; mix just until combined. Add the remaining flour mixture; mix just until combined.
Fold in the grated apple.
Divide the batter evenly between the prepared muffin cups.
Place the muffins in the preheated oven, then immediately reduce the oven temperature to 375°F. Bake the muffins for about 25 minutes, or until a toothpick inserted in the center comes out clean.
Transfer the muffins to a wire rack.
When the muffins are cool enough to handle (but still warm), prepare the topping.
Place the melted butter in a small bowl. In a separate small bowl, stir together the sugar and cinnamon.
Brush the top of each warm muffin with the melted butter, then roll in the cinnamon-sugar.