Taze böreğin kokusunu alınca hemen yemeden edemiyorum.

Because Turkish is saying the smell of the fresh börek.

That requires the first noun, börek, to take the genitive ending:

• börek = börek
• böreğin = of the börek

There is also a sound change:

• final k often softens to ğ before a vowel suffix
• so börek + in becomes böreğin

So taze böreğin kokusu means the smell of the fresh börek.

Because this is a possessed noun phrase.

In Turkish:

• koku = smell
• böreğin kokusu = the börek’s smell / the smell of the börek

The second noun gets a 3rd person possessive ending:

• koku
• kokusu = its smell

Then that whole phrase becomes the direct object of almak, so it also takes the accusative ending:

• kokusu + nu = kokusunu

So:

• böreğin kokusu = the smell of the börek
• böreğin kokusunu = the smell of the börek as the object

Alınca comes from almak plus -ınca.

• almak usually means to take, to get, or to receive
• -ınca / -ince means when, once, or as soon as

So literally:

• alınca = when (I) take/get

But here Turkish uses the expression koku almak, which means:

• to smell
• to catch a smell
• to notice a scent

So kokusunu alınca means:

• when I smell it
• when I catch its smell
• as soon as I smell it

Because koku almak and koklamak are not quite the same.

• koku almak = to catch/sense a smell
• koklamak = to sniff something deliberately

So in this sentence, the idea is not really I deliberately sniff the börek. It is more like:

• the smell reaches me
• I catch the smell
• once I smell it

That makes kokusunu alınca very natural here.

This is a very common Turkish pattern:

verb + -meden / -madan + edememek

It means:

• cannot help doing
• cannot refrain from doing
• cannot resist doing

So:

• yemeden edemiyorum = I can’t help eating
• more naturally: I can’t resist eating it

Breakdown:

• ye- = eat
• -meden = without eating / not eating
• edemiyorum = I cannot do/manage

The expression is idiomatic. You should learn it as a whole pattern:

• gülmeden edememek = can’t help laughing
• bakmadan edememek = can’t help looking
• aramadan edememek = can’t help calling

So hemen yemeden edemiyorum means I just can’t resist eating it right away.

Not in the usual English sense.

Even though the words may look like without eating, I can’t do, the actual expression means:

• I can’t help eating
• I can’t stop myself from eating
• I can’t resist eating

So it expresses an irresistible urge, not a general need for food.

Hemen means:

• immediately
• right away
• at once

It adds the idea that the reaction happens very fast.

So the sentence is not just:

• I can’t resist eating it

It is specifically:

• as soon as I smell it, I want to eat it right away

Because Turkish often leaves out subject pronouns when the verb ending already shows the subject.

Here:

• edemiyorum ends in -um, which shows 1st person singular
• so I is already built into the verb

That is why ben is not necessary.

You could say Ben taze böreğin kokusunu alınca... but that would add emphasis, like As for me...

The object is understood from context: the börek.

Turkish often leaves out something if it is already obvious. Since the whole sentence is about the smell of fresh börek, yemek naturally means eat the börek.

If you wanted to say it more explicitly, you could say something like:

• onu hemen yemeden edemiyorum = I can’t help eating it right away

But leaving it out sounds very natural.

It describes börek.

So the phrase means:

• the smell of fresh börek

not:

• the fresh smell of börek

This is because taze comes directly before böreğin:

• taze böreğin kokusu = the smell of fresh börek

If Turkish wanted to say the fresh smell, the wording would be different.

No, Turkish word order is flexible, but this sentence uses a very natural structure.

Current order:

• Taze böreğin kokusunu alınca = when I smell the fresh börek
• hemen yemeden edemiyorum = I can’t help eating it right away

This order works well because the when-clause comes first, setting up the situation before the main result.

Turkish usually keeps the main verb near the end, so edemiyorum being final is very normal.

-ınca / -ince can cover both ideas, depending on context.

In this sentence, because of hemen and the idea of an immediate reaction, it strongly suggests:

• as soon as I smell it

Without that context, -ınca can also simply mean:

• when
• once

So here the most natural feeling is:

• When / as soon as I catch the smell of fresh börek, I can’t resist eating it right away.