When Sheldon is sick in "The Pancake Batter Anomaly", he goes to The Cheesecake Factory to get some soup. After some debate about the availability of soup, Penny asks him what soup he wants. Penny ends up taking the day off, taking him home and taking care of him.
Sheldon tells Penny that when he was younger, his mother used to make him split pea with little frankfurter slices and homemade croutons. Penny tells him that they have "Chicken Tortilla and Potato Leek." and Sheldon asks her if he could have those with little frankfurter slices and home made croutons to which Penny says no.