This is a classic in the anglosphere. Bread, cheese, and onions. Though, in this image, it looks like there's some butter on the bread, which for me, is too exotic for my tastes.
I don't remember where I learned about this delicacy but I took the image from an open source information repository that calls itself "Free Encyclopedia".
Would anyone like to come over to my place for bread, cheese, and onions?
Your coworker sounds like my type of bloke. Tell him I'd like to eat some onions with him if he doesn't mind.