Chocolate

Preface: While both kids were watching a video, Dad stealthily retrieved a special candy bar from his stash and ate it.

Setting: About 10 minutes later Emma climbs up on Dad's lap and sits down. She watches the video over Dad's shoulder.
Emma: "What's that smell?"
Dad (knowing but trying to deflect): "What smell? Maybe it's the flowers." (Roses on the counter 2 feet away.)
Emma (looking directly at Dad): "Do you smell? ... That's chocolate."