In a large bowl stir together flour, sugar, baking powder, and salt. Make a well in the center of flour mixture; set aside.
In a medium bowl combine eggs, milk, oil, and vanilla. Add egg mixture all at once to flour mixture. Stir just until moistened (batter should be slightly lumpy). Stir in the 1/2 cup crumbled bacon and the 1/4 cup chopped apple.
Add batter to a preheated, lightly greased waffle baker according to the manufacturer's directions (use a regular or Belgian waffle baker). Close lid quickly; do not open until done. Bake according to the manufacturers directions. When done, use a fork to lift waffle off grid. Repeat with the remaining batter. Serve warm. If desired, top with the 2/3 cup coarsely chopped apple and the 3 slices crumbled bacon and serve with syrup.