Quite so, when a kettle, or even more so, a copper, in past centuries, was often a good way to cook & even to reheat deliciously moist, satisfying, economical & nutritious soup that fed everybody in the family plus friends as well.  

Waiter! There is a NRL grand final ticket in my soup!  

Oops, sorry, ma'am. That should have been one for the AFL grand final.  

Waiter! There's a model of the Sydney Opera House in my soup!

Oh I am most dreadfully sorry, madame, it was given to you by mistake, when we should have given you a model of the neighbouring Toast Rack building, containing the croutons to go with your kangaroo tail soup.  

Waiter! There is a winged Melbourne tram in my soup!  

@Courtenay: Oops, sorry, ma'am. That should have been one for the AFL grand final. 

Hmmm, perhaps you're being invited to a cricket game?

Waiter! There is a small blue ox in my soup!

I'm sorry, Sir, a child at the next table is playing with plastic toy animals, and accidentally threw it towards your table. 

Waiter, there's a mirror in my soup!

Our pleasure, & I hope you find it most useful! A mirror is one of those items that are often necessary, but are seldom around when you want one. 

Waiter! There is a small torch in my soup!

Madam, you ordered a light meal. 

Waiter, there's a pair of spectacles in my soup!

All the better for you to read the words in the alphabet soup you ordered from the menu.  

Waiter! There is a carved depiction of a lion in my soup! 

Yes, madame. You ordered stone soup and we use high-quality, carved stones for our soup.

Waiter, there's a library card in my soup!

Yes, of course there is! It is a Welcome to the district, waterproof library card. This is our Municipal Council's initiative, when we are proud of how much of local heritage is available for residents & visitors to see, the wide range of sporting & cultural interests & our well-run local services and amenities, information about all of which can be found in our well-stocked library. 

Waiter! There is a boomerang in my soup! 

Indeed, Sir. It is a token to allow you to *Return* your soup bowl for a free refill.

Waiter, there's an emerald in my soup!

Thank you for calling it to our attention, ma'am. You may be asked to give a statement to a police officer as another patron reported the theft of an emerald necklace earlier this evening.

Waiter, there's a teapot in my soup!

Oh dear! I'm so very sorry. You see, it's quite strange: from time to time odd things turn up in our rabbit stew--teapots... teacups... playing cards... why, once there was even a lovely gold pocket watch!

Waiter, there's a tree in my soup!

Congratulations, madame! You can take it home and plant it for shade.

Waiter, there's a bucket in my soup!

No, your soup is in the bucket! We pride ourselves on our huge portion sizes!

(I can actually see the cheesy restaurant commercial for this. )

Waiter, there's a cough drop in my soup!