Meanwhile, combine flour, sugar, baking powder and salt in a large bowl; whisk together to blend.
Pour milk in a glass measuring cup and microwave for 1 minute at full power to heat slightly.
Pour into medium bowl; whisk in melted butter and eggs.
Add liquid ingredients to flour mixture, whisking just until blended.
Grease waffle iron with cooking spray.
Spread about 1/3 cup batter over each iron (or appropriate amount according to manufacturer's directions) and sprinkle 1/8 of bacon on top. Close waffle iron and cook until done. Repeat with remaining batter and bacon.