Eggs Benedict Promise

Listen here, numbskull. The joke is that the person wasn't planning to visit their family, but changed their mind because their mom promised to make them Eggs Benedict. The punchline is that they're really just going home for the hollandaise sauce, which is a key part of Eggs Benedict. It's funny because it shows the person is motivated by the sauce, not necessarily family. Since you like manga, this is like saying you only watch anime for the plot *wink*.