Preheat oven to 375 F. Line 12 muffin cups with liners, or spray with baking spray.
In a large bowl, combine flour, sugars, baking powder , cinnamon, and salt. Make a well in center of flour mixture; set aside.
In another bowl, combine eggs, milk, melted butter, and vanilla. Peel and grate the apple; add grated apple to this wet mix.
Add mixture all at once to the flour mixture, along with the blueberries. Stir just until moistened (batter should be lumpy.) Divide batter between 12 prepared muffin cups, filling each to almost full.
Bake in a 375 degree F oven for 18 to 20 minutes or until golden and a wooden toothpick inserted in centers comes out clean.
Cool in muffin cups on a wire rack for 5 minutes. Remove from muffin cups; serve warm.