Prenu kiun ajn kuleron vi volas, sed uzu tiun pladon por la fromaĝo.

The ending -u is the Esperanto volitive ending. It is used for commands, requests, suggestions, and similar ideas.

So:

• preni = to take
• prenu = take
• uzi = to use
• uzu = use

In this sentence, the speaker is giving instructions, so -u is exactly the right form.

Ajn adds the idea of any / whichever / no matter which.

So kiun ajn means something like whichever or any one that.

In this sentence, Prenu kiun ajn kuleron vi volas means that the listener may choose freely among the available spoons. The exact identity of the spoon does not matter.

This is a very common question.

• kiu asks about identity: which one?
• kia asks about quality or type: what kind of?

Here the idea is take whichever spoon you want, meaning choose any individual spoon. That is a question of identity, not type, so kiu is correct.

If you said kian ajn kuleron, it would sound more like any kind of spoon, focusing on type rather than on choosing one specific spoon from several.

Both are in the accusative because they belong to the direct object of prenu.

• kuleron has -n because it is the thing being taken.
• kiun also has -n because it agrees with the noun phrase and functions in that same object relationship.

Esperanto marks direct objects with -n, and words that go together in the noun phrase often show matching grammar.

So:

• kulero = spoon
• kuleron = a spoon / the spoon as direct object

And similarly:

• kiu = which
• kiun = which one, as direct object

It is essentially whichever spoon you want.

A natural way to understand it is:

• kiun ajn kuleron = whatever spoon / whichever spoon
• vi volas = you want

So the whole part means whichever spoon you want.

Esperanto often uses this structure very directly, without needing an extra word like that. English says the spoon that you want or whichever spoon you want; Esperanto can simply say kiun ... vi volas.

Yes, but the meaning changes slightly.

• Prenu iun ajn kuleron = take any spoon
• Prenu kiun ajn kuleron vi volas = take whichever spoon you want

The shorter version simply allows any spoon. The longer version emphasizes the listener’s personal choice: choose the one you want.

So they are similar, but kiun ajn ... vi volas sounds a bit fuller and more explicit.

Because the sentence means whichever spoon you want, and in Esperanto the present tense is normally used for that idea.

• vi volas = you want

Even though the whole sentence is a command about the future, the wanting is viewed as your present preference at the moment of choosing.

This matches English fairly well, since English also says whichever spoon you want, not usually whichever spoon you will want.

Tiu means that. It points to a specific item.

So:

• tiu plado = that plate / that dish
• tiun pladon = that plate / that dish as direct object

It has -n because it is the object of uzu.

The speaker is not saying just use a plate. The speaker is saying use that particular plate.

Sed means but.

It connects the two instructions:

• Prenu kiun ajn kuleron vi volas = Take whichever spoon you want
• sed uzu tiun pladon por la fromaĝo = but use that plate for the cheese

So the contrast is:

• free choice for the spoon
• a specific choice for the plate

That contrast is exactly why sed is used.

Por means for. It shows purpose or intended use.

So uzu tiun pladon por la fromaĝo means use that plate for the cheese, in the sense of that is the plate intended for the cheese.

Other prepositions would give different meanings:

• kun la fromaĝo = with the cheese
• de la fromaĝo = of/from the cheese
• sur la fromaĝo = on the cheese

Only por gives the idea of intended function here.

La is the definite article, meaning the.

In this sentence, la fromaĝo most naturally refers to some specific cheese already understood in the situation, such as the cheese being served at the table.

Esperanto often uses la when the speaker and listener can identify the thing from context. So here it is not just cheese in general, but the cheese relevant to the situation.

In some contexts, Esperanto can omit la more often than English would, but in this sentence la fromaĝo sounds very natural because a specific cheese is meant.