Perhaps you might be correct if we think in that way.I'd go for "were" or "are" myself because it seems to say that the individual components of bread-and-butter, namely bread and butter, are on the table. If it referred to buttered bread, I'd expect There is/was bread and butter on the table, but maybe that's just me.
We still need to know if this refers to the past or the present of course.
Yeah, even I chose your former opinion.If the question offers was and were as the two possible answers, you should probably choose was. However, either form is possible, depending on whether the speaker is thinking of "bread and butter" as a single entity (as in "dinner is on the table") or as two ingredients ("the roast and vegetables are on the table").