Learn Croatian: Ova mjera je točna, stavi toliko maslaca. - This measurement is exact, put that much butter.

Toliko means "that much" and is used to refer to amounts near the listener or, in this case, to an amount that was just mentioned. Since the measurement was just established in the first half of the sentence (Ova mjera je točna), we use toliko to point back to it. If you were physically holding up a cup and showing the amount to someone, you would use ovoliko (this much).

Why is maslaca in the genitive case?

In Croatian, any word expressing a quantity—like toliko (that much), ovoliko (this much), malo (a little), or puno (a lot)—must be followed by the genitive case. You can think of it as literally saying "put that much of butter".

Is stavi an imperative (command) form?

Yes, stavi is the informal imperative form for "you" (singular), coming from the perfective verb staviti (to put). Just like in English, we drop the pronoun ti (you) when giving a direct command.

I usually see točna translated as "correct". Does it mean "exact" here?

Yes! The adjective točan (or točna to match the feminine noun mjera) means "correct", but it is also the standard word for "exact", "accurate", or even "on time". In this context, it means the measurement is perfectly accurate.