Spaghetti jaffle is a traditional sandwich that's also quite popular in Japan. The sandwich usually consists of spaghetti, a bread roll or sliced bread, butter, grated cheese, and a sauce (often tomatoes and onions). The spaghetti are cooked until al dente, or you can just use leftover spaghetti.

The pasta is cooked with the sauce. The bread is split, buttered, and each slice is topped with the spaghetti, sauce, and grated cheese. The slices are joined into a sandwich that is often cooked until the bread is well toasted, although it can also be served cold.