Denise is a waitress at Cousin Oliver's.
Denise gives Sam and Dean their menu when the brothers sit down at a booth. She shows immediate interest in Dean, but since Dean is in a foul mood, he simply tells her he's waiting for somebody. She drops their menus and stomps off.
When Adam arrives, Denise is pleased to see him and gives him a glass of water, which Dean snatches. Denise eyes him angrily, then asks Adam if he wants the usual. She later returns to give Adam his meal.