The phrase "similar soup" is an idiomatic expression that means a situation or circumstance in which two things are very similar, often to the point where they appear almost identical. The term comes from the idea that different types of soup may have some ingredients and flavors that vary, but at their core, they all share many common elements, making them "similar" in nature. In other words, while there might be small differences between two things, overall they are quite similar to one another.