В этой булочной по выходным пекут тёплые круассаны и сладкие булки.

Because в means in/at here, and when в expresses location, Russian normally uses the prepositional case.

So the base forms are:

• эта булочная = this bakery
• в этой булочной = in this bakery / at this bakery

What changes:

• эта → этой
• булочная → булочной

A useful extra note: булочная is one of those nouns that historically comes from an adjective, so it declines with adjective-like endings. That is why you see -ой here, not the more typical -е that many feminine nouns have in the prepositional.

Этой is the feminine singular prepositional form of этот.

The noun булочная is feminine singular, so the demonstrative has to match it in:

• gender: feminine
• number: singular
• case: prepositional

So:

• этот = this
• эта булочная = this bakery
• в этой булочной = in this bakery

Russian words that describe a noun must agree with it, so этой matches булочной.

По выходным means on weekends or at weekends, especially in the sense of something that happens regularly.

This is a very common Russian pattern:

• по
  • dative plural = a repeated time pattern

So:

• выходные = weekend days / the weekend
• по выходным = on weekends, every weekend, at weekends

This expression emphasizes habitual repetition.

A helpful comparison:

• по выходным = on weekends, as a general routine
• в выходные = on the weekend / during the weekend, often more tied to a specific occasion or time frame

Both can be possible in many contexts, but по выходным is especially natural for regular habits.

It is dative plural.

That is because the preposition по often requires the dative, and in this time-expression pattern it specifically gives the sense of on weekends / every weekend.

So the form works like this:

• dictionary form: выходные
• dative plural: выходным
• phrase: по выходным

Even though выходные often looks like an adjective, it is very commonly used like a noun meaning the weekend or days off.

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

So пекут literally means they bake, but in this kind of sentence it often means something like:

• they bake
• people bake
• the bakery bakes
• warm croissants and sweet buns are baked

English often chooses a smoother translation than literal they.

So in this sentence, the focus is not on who bakes them, but on the fact that this bakery bakes them on weekends.

This is called an indefinite-personal construction.

Пекут is the 3rd person plural present tense form of печь, which means to bake.

This verb is a bit irregular:

• я пеку = I bake
• ты печёшь = you bake
• они пекут = they bake

The sentence uses the imperfective verb печь because it describes a habitual, repeated action:

• по выходным пекут = they bake on weekends / they bake every weekend

If Russian used a perfective verb such as испечь, it would suggest a completed result rather than a regular repeated activity.

They are in the accusative plural, because they are the direct objects of пекут.

But with inanimate nouns, the accusative plural is the same as the nominative plural.

So:

• круассаны = nominative plural / accusative plural
• булки = nominative plural / accusative plural

That is why they look unchanged.

If these were animate nouns, the accusative plural would usually match the genitive plural instead.

Russian adjectives must agree with the nouns they describe in gender, number, and case.

Here are the matches:

• этой булочной

  • feminine
  • singular
  • prepositional

• тёплые круассаны

  • plural
  • accusative
  • inanimate, so accusative plural looks like nominative plural

• сладкие булки

  • plural
  • accusative
  • inanimate, so again the form looks like nominative plural

So the adjective endings are not random; they simply follow the nouns they belong to.

Yes. Russian word order is fairly flexible.

This sentence starts with:

• В этой булочной = setting the place first
• по выходным = then the time
• пекут... = then the action

That order sounds natural because it introduces the background first, then tells you what happens there.

Other orders are possible, for example:

• По выходным в этой булочной пекут тёплые круассаны и сладкие булки.
• Тёплые круассаны и сладкие булки пекут в этой булочной по выходным.

These versions are grammatically fine, but the emphasis changes slightly.

Russian word order often helps show focus and information flow, not just grammar.

They are related, but they mean different things.

• булочная = bakery, bread shop
• булка = bun, roll, bread loaf, depending on context
• булки = buns

So in this sentence:

• в этой булочной = in this bakery
• сладкие булки = sweet buns

This is a nice example of related Russian words having different grammatical roles and meanings in the same sentence.

Literally, it means warm croissants.

But in bakery or food contexts, тёплые often suggests that they are freshly baked, still warm, and therefore especially appealing.

So depending on the translation style, a natural English rendering might be:

• warm croissants
• fresh warm croissants
• freshly baked warm croissants

The Russian itself is still simply тёплые; the extra idea comes from the context.