Za doručak jedem kiflu sa salamom.

Yes. Za doručak is the normal Croatian way to say for breakfast.

• za = for
• doručak = breakfast

So Za doručak jedem kiflu sa salamom means literally something like For breakfast, I eat a bread roll with salami.

In Croatian, za + meal word is very common:

• za doručak = for breakfast
• za ručak = for lunch
• za večeru = for dinner

It often tells you what someone eats on that occasion.

Because za here takes the accusative case, and doručak is a masculine noun whose accusative singular looks the same as the nominative singular.

So:

• nominative: doručak
• accusative: doručak

That is normal for many masculine inanimate nouns in Croatian.

So even though the case changes grammatically, the form stays the same.

Because kiflu is the accusative singular form of kifla.

Here, kifla is the direct object of jedem (I eat), so Croatian uses the accusative.

• nominative: kifla
• accusative: kiflu

This is very common for feminine nouns ending in -a:

• imam knjigu = I have a book
• vidim ženu = I see a woman
• jedem kiflu = I eat a bread roll

So kiflu is there because it is the thing being eaten.

Because after s/sa meaning with, Croatian uses the instrumental case, not the accusative.

So:

• nominative: salama
• instrumental: salamom

That is why you get:

• sa salamom = with salami

Compare:

• jedem salamu = I eat salami
  Here salamu is the direct object, so it is accusative.
• kifla sa salamom = a bread roll with salami
  Here sa requires instrumental, so salamom is instrumental.

Both s and sa can mean with.

Sa is often used instead of s to make pronunciation easier, especially before certain consonants or consonant clusters. Since s salamom would sound awkward, Croatian uses sa salamom.

So:

• s prijateljem = with a friend
• sa sestrom = with a sister
• sa salamom = with salami

In many situations, the choice is about sound and ease of pronunciation rather than a big difference in meaning.

Kifla is a kind of bread roll or pastry, often crescent-shaped. Depending on context, English translations can vary:

• bread roll
• crescent roll
• sometimes just roll

In this sentence, kifla sa salamom is basically a roll with salami inside or served with salami.

It is a very everyday food word in Croatian and neighboring languages.

Because Croatian often leaves out subject pronouns when they are already clear from the verb form.

Here:

• jedem already means I eat

So ja is not necessary.

Compare:

• jedem = I eat
• jedeš = you eat
• jede = he/she/it eats

You can add ja for emphasis:

• Ja jedem kiflu sa salamom. = I eat a roll with salami.

But in a normal neutral sentence, Croatian usually drops it.

Usually it is understood as a habitual or general statement:

• For breakfast, I eat a roll with salami.
• I eat a roll with salami for breakfast.

The Croatian present tense often covers both:

• something happening now
• something someone does regularly

Context tells you which meaning is intended. Because of Za doručak, the sentence most naturally sounds like a routine or usual choice.

Yes. Croatian word order is more flexible than English word order.

The given sentence is natural:

• Za doručak jedem kiflu sa salamom.

But you could also hear:

• Jedem kiflu sa salamom za doručak.
• Kiflu sa salamom jedem za doručak.

These all mean roughly the same thing, but the emphasis changes a little.

• Za doručak... puts the breakfast context first.
• Kiflu sa salamom... emphasizes what is being eaten.
• Jedem... starting with the verb can sound more neutral in conversation depending on context.

It describes the kiflu.

So kiflu sa salamom means:

• a roll with salami

It is not really saying I eat with salami as a separate adverbial idea. Instead, it is a noun phrase:

• kifla = roll
• sa salamom = with salami

Together: roll with salami

Croatian has no articles like English a/an/the.

So kiflu could mean:

• a roll
• the roll

The exact meaning depends on context.

In this sentence, English would usually translate it as:

• For breakfast, I eat a roll with salami.

But Croatian itself does not mark that distinction with articles.

More or less, yes, but not always in a perfectly one-to-one way.

In everyday Croatian, salama refers to a type of sausage/cold cut, and in many contexts salami is a good English translation. But the Croatian word can sometimes be broader than English salami.

In this sentence, translating sa salamom as with salami is completely natural and appropriate.