In a medium mixing bowl, stir together the whole-wheat flour, all-purpose flour, baking soda, baking powder, and salt. Make a well in the center of the dry ingredients; set aside.
In another medium mixing bowl, beat eggs. Stir in buttermilk and cooking oil. Add all at once to the dry ingredients. Stir just until moistened (batter should be lumpy). Stir in blueberries or apple, if you like.
For each pancake, pour about 1/4 cup of the batter on a hot, lightly greased griddle or heavy skillet. Cook over medium heat for about 2 minutes on each side or until pancakes are golden brown, turning when pancakes have bubbly surfaces and edges are slightly dry. Serve warm with butter, syrup or other toppings. Makes 14 pancakes.