Der Koch bereitet heute im Restaurant eine Suppe aus Kürbis und Sellerie vor.

Because the verb here is vorbereiten (to prepare), which is a separable verb.

In a normal main clause, German splits it:

• bereitet goes in the usual verb position
• vor goes to the end

So:

• Der Koch bereitet ... vor.

In an infinitive or with a modal verb, it stays together:

• Der Koch will eine Suppe vorbereiten.

German main clauses usually follow the V2 rule: the finite verb goes in the second position.

Here, the first position is taken by Der Koch, so the finite verb bereitet comes next:

• Der Koch | bereitet | heute im Restaurant eine Suppe ... vor.

If you move another element to the front, the verb still stays second:

• Heute bereitet der Koch im Restaurant eine Suppe ... vor.
• Im Restaurant bereitet der Koch heute eine Suppe ... vor.

Because Der Koch is the subject of the sentence, so it is in the nominative case.

• der Koch = nominative masculine singular
• den Koch = accusative masculine singular

Since the cook is the one doing the action, nominative is required.

Because eine Suppe is the direct object of vorbereiten, so it is in the accusative case.

The noun Suppe is feminine:

• nominative: eine Suppe
• accusative: eine Suppe

So the form looks the same in both cases, but here its role is accusative because it is the thing being prepared.

Because im Restaurant describes a location: where the action happens.

• im = in dem
• with in, German uses:
  • dative for location: im Restaurant = in the restaurant
  • accusative for movement/destination: ins Restaurant = into the restaurant

So:

• Der Koch bereitet ... im Restaurant vor. = He is already there.
• Der Koch geht ins Restaurant. = He goes into the restaurant.

It uses the dative case.

That is because in is a two-way preposition:

• location → dative
• direction/movement toward somewhere → accusative

Here it is location, so:

• in dem Restaurant → im Restaurant

Aus always takes the dative case.

So grammatically, Kürbis and Sellerie are in the dative here.

However, since there is no article before them, you do not see a special dative ending:

• aus Kürbis
• aus Sellerie

If there were articles, you would see the case more clearly:

• aus dem Kürbis (not natural here in meaning, but it shows the dative form)
• aus dem Sellerie

German often leaves out articles when talking about ingredients or materials in a general sense.

So eine Suppe aus Kürbis und Sellerie sounds natural, like:

• a soup made from pumpkin and celery

You could sometimes hear forms with articles in other contexts, but with ingredients, zero article is very common.

Compare:

• ein Saft aus Orangen
• eine Suppe aus Kürbis
• Salat mit Tomaten

Because one preposition can govern two coordinated nouns.

So:

• aus Kürbis und Sellerie

means:

• aus Kürbis und aus Sellerie

German usually does not repeat the preposition unless there is a special reason for emphasis or clarity.

Heute is a time expression, and German is fairly flexible about where such elements go.

In this sentence, it comes after the verb:

• Der Koch bereitet heute ... vor.

That is very natural.

You could also move it to the first position:

• Heute bereitet der Koch im Restaurant eine Suppe aus Kürbis und Sellerie vor.

Both are correct. The difference is mostly one of emphasis or focus.

German word order in the middle of the sentence can vary, but there are common patterns.

Here:

• heute = time
• im Restaurant = place
• eine Suppe = direct object

This order is natural and understandable. German often prefers a fairly organized middle field, and adverbial information like time and place commonly comes before a full noun object.

You may also hear other orders depending on emphasis, for example:

• Der Koch bereitet heute eine Suppe im Restaurant vor.

That is also possible, but the original sentence sounds very normal.

Not exactly.

• kochen = to cook
• vorbereiten = to prepare

Vorbereiten is broader. It can include:

• cutting ingredients
• getting things ready
• starting the dish
• generally preparing it

So in this sentence, vorbereitet does not necessarily focus only on the cooking itself.

Yes, absolutely.

German often moves the element you want to emphasize into the first position, while the finite verb stays second:

• Heute bereitet der Koch im Restaurant eine Suppe aus Kürbis und Sellerie vor.

That version puts more focus on today.

The original version puts Der Koch first, which makes the cook the topic.

Because in German, all nouns are capitalized.

So in this sentence:

• Koch
• Restaurant
• Suppe
• Kürbis
• Sellerie

are all capitalized because they are nouns.

This is one of the most noticeable spelling differences between German and English.