На завтрак я поджарю хлеб в тостере.

На завтрак is the normal idiomatic way to say for breakfast / as breakfast in Russian.

• На завтрак = for breakfast
• similarly:
  • на обед = for lunch
  • на ужин = for dinner

Для завтрака usually means for breakfast in a more literal-purpose sense, but it is much less natural here. In everyday Russian, when talking about what someone eats or makes for a meal, на + meal is the usual pattern.

So:

• На завтрак я поджарю хлеб в тостере. = natural
• Для завтрака я поджарю хлеб... = possible in some contexts, but not the normal everyday phrasing

Yes, я can be omitted.

Russian often drops subject pronouns when the verb form already makes the subject clear. Here поджарю clearly means I will toast, so я is not strictly necessary.

Compare:

• На завтрак я поджарю хлеб в тостере.
• На завтрак поджарю хлеб в тостере.

Both are grammatical. Including я can:

• add emphasis
• make the sentence clearer
• sound a bit more explicit or contrastive

For example, я might be used if the speaker is stressing that they will do it.

Поджарю is the 1st person singular future form of поджарить.

The verb поджарить means something like:

• to toast
• to brown lightly
• to fry/roast a bit

In this sentence, with хлеб and в тостере, it naturally means to toast.

The prefix под- often gives the idea of doing something a little or until lightly done/browned. So поджарить хлеб is very natural for to toast bread.

Because поджарить is a perfective verb.

In Russian:

• imperfective verbs have a true present tense
• perfective verbs do not have a present tense; their “present-looking” forms refer to the future

So:

• поджарю = I will toast
• not I toast / I am toasting

This is a very common Russian pattern.

For comparison:

• я жарю = I am frying / I fry
  (imperfective, present)
• я поджарю = I will toast / I will brown
  (perfective, future)

Russian often says поджарить хлеб where English might say make toast or toast some bread.

So the focus is on the bread being toasted, rather than using a separate noun like toast.

Russian does have words such as:

• тост = a toast (usually the spoken kind at a celebration)
• тосты can also mean pieces of toast in some contexts

But in an ordinary sentence about breakfast, поджарить хлеб is very natural and often the most straightforward way to say it.

So even though English often uses the noun toast, Russian commonly uses bread plus a verb: to toast bread.

Хлеб is in the accusative case, because it is the direct object of поджарю.

The speaker is doing something to the bread, so the bread is the object.

For an inanimate masculine noun like хлеб, the accusative singular looks the same as the nominative singular:

• nominative: хлеб
• accusative: хлеб

So the form does not change, but the function does.

Because в here means in, and тостере is the required case form after в when talking about location.

So в тостере literally means:

• in the toaster

This is the natural Russian way to express that the bread is being toasted inside the appliance.

English often says in the toaster too, so this matches quite well.

Тостере is the prepositional case singular of тостер.

The basic noun is:

• тостер = toaster

After в when it means in and expresses location, Russian normally uses the prepositional case:

• в тостере = in the toaster

So:

• dictionary form: тостер
• prepositional singular: в тостере

Not in this sentence, if you want the normal meaning.

• в тостере = in the toaster
• с тостером = with the toaster

С тостером would sound like the toaster is accompanying you, or that you are doing something together with it, which is not what is meant here.

When Russian talks about preparing food using an appliance as the place/process, it often uses в:

• в духовке = in the oven
• в микроволновке = in the microwave
• в тостере = in the toaster

So в тостере is the natural choice.

No, Russian word order is fairly flexible.

На завтрак я поджарю хлеб в тостере. is a very natural neutral sentence. It puts на завтрак up front, which sets the context: for breakfast.

Other word orders are possible, but they shift emphasis slightly. For example:

• Я поджарю хлеб в тостере на завтрак.
  More focus on what I will do
• Хлеб я поджарю в тостере на завтрак.
  More contrastive focus on bread
• В тостере я поджарю хлеб на завтрак.
  More focus on the toaster

So the original word order is not the only possible one, but it is a natural default if the speaker wants to begin with for breakfast.

Russian has no articles like a/an/the.

So:

• хлеб can mean bread, some bread, or the bread
• тостере can mean in a toaster or in the toaster

The exact meaning depends on context.

In this sentence, English would most naturally say something like in the toaster, but Russian does not need a separate word for that.

Usually поджарю is better here.

Both verbs are related to frying/roasting, but they are not identical:

• жарить / пожарить = to fry, roast, cook by frying
• поджарить = to brown, toast, fry a little, make lightly crisp

With хлеб в тостере, поджарить is the natural choice because toast is typically lightly browned.

If you said пожарю хлеб, it could sound more like I’ll fry the bread, which is not the normal idea of using a toaster.

So in this sentence, поджарю fits the situation best.

The imperfective partner is usually поджаривать (or sometimes the more general жарить, depending on context).

Compare:

• Я поджарю хлеб в тостере.
  I will toast the bread
  Perfective: one completed action/result

• Я буду поджаривать хлеб в тостере.
  I will be toasting bread in the toaster
  Imperfective: process, repeated action, or less focus on completion

In everyday speech, the perfective поджарю is more natural here because the speaker is talking about a single future result: the bread will get toasted.

So the perfective is a very good fit for a simple breakfast plan.