Za doručak jedem jaje i hleb.

In Serbian, za + accusative is often used to mean for in the sense of a meal, occasion, or purpose.

So:

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

Here, doručak is in the accusative singular, but for this noun the form looks the same as the dictionary form.

So Za doručak jedem jaje i hleb literally feels like For breakfast, I eat egg and bread.

Serbian often drops subject pronouns when they are clear from the verb form.

• jedem already means I eat
• the ending -m shows 1st person singular

So:

• Jedem = I eat
• Ja jedem = I eat with extra emphasis, contrast, or clarity

You would use ja if you want to stress it, for example:

• Ja jedem jaje, a on jede sir.
  I eat an egg, and he eats cheese.

In a normal sentence, leaving out ja is more natural.

Jedem is the 1st person singular present tense of the verb jesti = to eat.

A few present-tense forms are:

• ja jedem = I eat
• ti jedeš = you eat
• on/ona/ono jede = he/she/it eats
• mi jedemo = we eat
• vi jedete = you eat
• oni/one/ona jedu = they eat

In this sentence, the present tense can describe a regular habit:

• Za doručak jedem jaje i hleb.
  = I eat egg and bread for breakfast.

Yes, they are direct objects, so they are in the accusative case.

However, in Serbian, some nouns have the same form in nominative and accusative.

That is what happens here:

• jaje is a neuter singular noun
  nominative: jaje
  accusative: jaje
• hleb is a masculine inanimate noun
  nominative: hleb
  accusative: hleb

So even though they are objects, their forms do not change visibly in this sentence.

Serbian does not have articles like English a/an and the.

So:

• jaje can mean an egg, the egg, or just egg
• hleb can mean bread, some bread, or the bread

The exact meaning depends on context.

That is very normal in Serbian, and learners need to get used to relying on context instead of articles.

Hleb is usually treated as a mass noun, like English bread.

So Serbian normally says:

• jedem hleb = I eat bread

not a plural form meaning breads.

If you want to talk about separate loaves, pieces, or slices, Serbian usually uses another noun:

• hleb = bread
• kriška hleba = a slice of bread
• komad hleba = a piece of bread

So in this sentence, hleb works just like English bread.

It is singular because the sentence is talking about one egg or about a typical breakfast item in a general sense.

• jaje = egg
• jaja = eggs

So you could also say:

• Za doručak jedem jaja i hleb.
  = I eat eggs and bread for breakfast.

Both are possible, depending on what you mean.

If you want to emphasize the number one, you can say:

• jedno jaje = one egg

But if the number is not important, Serbian often just uses the noun without one.

Yes, you could.

Serbian word order is more flexible than English word order because case endings help show grammatical roles.

These are all possible, with slightly different emphasis:

• Za doručak jedem jaje i hleb.
  Focuses first on for breakfast
• Jedem jaje i hleb za doručak.
  Starts with the action
• Jaje i hleb jedem za doručak.
  Emphasizes what you eat

The version you were given is very natural and common.

I simply means and.

So:

• jaje i hleb = egg and bread

It connects the two objects of the verb jedem.

This is one of the easiest Serbian words to remember because it is extremely common:

• mama i tata = mom and dad
• sir i mleko = cheese and milk

A simple pronunciation guide is:

• Za doručak jedem jaje i hleb
  roughly: zah doh-ROO-chak YEH-dem YAH-yeh ee hlehb

A few notes:

• doručak has č, pronounced like ch in church
• j in Serbian is pronounced like English y
• so jaje sounds like YAH-yeh
• hleb begins with a real h sound

If you are learning standard Serbian pronunciation, it is also useful to know that stress is important, but beginners can first focus on clear sounds.

Hleb is the standard Serbian word, especially in Serbia.

But you may also see regional variants in the wider South Slavic area:

• hleb = common in Serbian
• hljeb = common in some ijekavian varieties
• kruh = common in Croatian

So if you are learning standard Serbian, hleb is exactly the form you want here.