The Large Hadron Collision - S3-E15
Corrected entry: The "Hollermus" that Sheldon allegedly makes is not actually a Swiss breakfast dish. It is in fact simply a kind of jam made from elderberries which is quite common in most German-speaking countries. Also, judging by the ingredients on the table (eggs, milk, butter) and the food on the plate, the dish prepared by Sheldon seems most likely to be an omelette with a Vienna sausage, which is in no way traditionally Swiss.
Correction: He actually says Cholermus which is a swish breakfast dish similar to a pancake, I had to find a script online when I first heard it to figure out what it was.