Heat oven to 375 degrees F. Coat standard-size muffin pan with 12 indentations with cooking spray.
In large bowl, mix flour, baking powder, cinnamon, salt, cloves.
In medium-size bowl, whisk egg, sugar, oil and vanilla. Add applesauce.
Make well in center of dry ingredients. Pour egg mixture into well; stir just until dry ingredients are moistened. Fold in diced apple. Divide among 12 muffin cups (1/3 cup each).
In clean bowl, mix butter, nuts, sugar and flour until crumbly. Sprinkle over tops of muffins.
Bake in 375 degree F oven until toothpick inserted in centers comes out clean, 22 to 25 minutes. Let cool in pan 5 minutes. Remove muffins to wire rack; let cool. Sprinkle with confectioners sugar just before serving, if desired. Makes 12 servings.