How to Make It
Preheat oven to 425°.
Lightly coat both sides of bread with cooking spray. Press each bread slice into the cup of a muffin tin. Bake at 425° for 10 minutes or until bread is lightly toasted. Cool slightly.
Reduce oven temperature to 350°.
Combine milk and eggs, stirring well with a whisk. Divide the egg mixture evenly among bread cups. Sprinkle onions, if desired, and bacon evenly over tarts; top each tart with 1 tablespoon cheese. Bake at 350° for 15 minutes or until set.