Эта слойка очень вкусная, потому что её только что достали из духовки.

In Russian, the verb to be is normally omitted in the present tense.

So:

• Эта слойка очень вкусная = This pastry is very tasty

Literally, it is closer to:

• This pastry very tasty

Using есть here would sound unnatural in normal speech. Russian uses есть mainly for meanings like there is / there exists or sometimes for emphasis, not as the ordinary present-tense is.

Because слойка is a feminine singular noun, and both the demonstrative эта and the adjective вкусная must agree with it.

Russian adjectives and words like this change depending on:

• gender
• number
• case

Here:

• эта = feminine singular nominative of this
• вкусная = feminine singular nominative of tasty
• слойка = feminine singular nominative

So all three match.

Compare:

• этот пирожок вкусный — this pie is tasty
• это печенье вкусное — this cookie is tasty

Слойка usually means a puff pastry or flaky pastry item made from layered dough.

The word comes from слой, meaning layer. So the idea is something layered or flaky.

Depending on context, слойка could be:

• a sweet pastry
• a savory puff pastry
• a pastry turnover-like item

So it is not always exactly the same as one single English pastry word, but puff pastry / flaky pastry is the basic idea.

Because вкусная describes the noun слойка, so it must be an adjective agreeing with that feminine noun.

• слойка is feminine singular
• therefore: вкусная

If you said вкусно, that would usually be an adverb or a neuter predicative form, more like:

• Это очень вкусно — This is very tasty / delicious

That sentence is also correct, but it is structured differently. In your sentence, the speaker is talking about the pastry itself, so вкусная is the natural form.

Because её is the object form of она.

In the clause:

• её только что достали из духовки

the pastry is not doing the action. It is receiving the action. Someone took it out of the oven.

So:

• она = she / it as the subject
• её = her / it as the object

Compare:

• Она очень вкусная — It is very tasty
• Её достали из духовки — They took it out of the oven

Even though слойка is inanimate, Russian still uses её for the feminine singular object pronoun.

Because достали agrees with an understood subject, not with её.

The hidden subject is something like:

• they took it out

Russian often uses 3rd person plural with no stated subject when the doer is unknown, obvious, or unimportant.

So:

• её только что достали из духовки

literally means:

• they just took it out of the oven

In natural English, we might translate that more smoothly as:

• it was just taken out of the oven

So the plural verb does not mean multiple pastries. It means an unspecified they.

Только что is a fixed expression meaning:

• just now
• a moment ago
• only just

So:

• её только что достали из духовки = it was just taken out of the oven

Do not translate it word-for-word as only what. As a phrase, it simply means very recently.

Достали is the past plural perfective form of достать.

Russian aspect matters a lot:

• perfective = a completed action, seen as a whole
• imperfective = an ongoing, repeated, or uncompleted action

Here, the idea is that the pastry has already been taken out, and that completed result matters now: it is hot and tasty.

So достали is the natural choice.

If you used the imperfective доставали, it would suggest something more like:

• they were taking it out
• they used to take it out
• the action is being described as a process or repeated event

That does not fit as well with только что and the completed result.

Because the preposition из requires the genitive case.

The basic noun is:

• духовка — oven

After из, it becomes:

• из духовки — out of the oven / from the oven

So:

• духовка = nominative
• духовки = genitive singular

This is very common in Russian:

• из дома — out of the house
• из магазина — from the store
• из коробки — out of the box

Here, из shows movement from inside something.

Because потому что introduces a subordinate clause meaning because.

So the sentence has:

• a main clause: Эта слойка очень вкусная
• a subordinate reason clause: потому что её только что достали из духовки

Russian punctuation normally separates those clauses with a comma:

• Эта слойка очень вкусная, потому что её только что достали из духовки.

This is very similar to English, where a because clause is often separated in writing depending on structure and style, but in Russian this comma is standard here.

Not completely. Russian word order is fairly flexible, but different orders change the focus or emphasis.

The version in your sentence is very natural and neutral:

• её только что достали из духовки

Other possible orders include:

• Только что её достали из духовки — emphasizes just now
• Из духовки её только что достали — emphasizes out of the oven

The basic meaning stays the same, but the information focus shifts.

So Russian word order is not random, but it is more flexible than English.

Yes, but the active 3rd person plural with an unspecified subject is often more natural.

Your sentence says:

• её только что достали из духовки

literally:

• they just took it out of the oven

A more passive-style version might be something like:

• Она только что была вынута из духовки

That is grammatical, but it sounds more formal or bookish in many contexts.

In everyday Russian, using an unspecified they is very common where English might prefer a passive:

• Мне сказали... — I was told...
• Дом построили в прошлом году — The house was built last year
• Её только что достали из духовки — It was just taken out of the oven

So the sentence you have is very natural colloquial Russian.