Learn Hardcore Chinese: guōdǐ suíbiàn, nǐ gǎodìng ba. - Any broth base is fine; you sort it out.

In everyday speech, especially in a hotpot context, 锅底 usually means the broth base / soup base / flavor base of the pot, not the physical metal bottom of the pot.

So here, 锅底 is shorthand for things like:

麻辣锅底 — spicy broth base
清汤锅底 — clear broth base
鸳鸯锅底 — split pot with two broths

The exact meaning depends on context, but in a restaurant conversation it almost always means which pot base to choose.

Why is 随便 used here? What does 锅底随便 mean exactly?

随便 here means whatever is fine / I don’t mind / anything works.

So 锅底随便 means something like:

Any soup base is fine
I’m okay with whatever for the pot base
I don’t care which broth base we choose

It sounds short and conversational. In full form, the speaker might mean:

锅底我都可以。
锅底选什么都行。
锅底随便你。

But in natural speech, Mandarin often leaves out words that are understood from context.

Is there an omitted word or structure in 锅底随便?