В этом кафе Вам подадут сытный салат, в который входят фасоль, кукуруза и петрушка.

Because в этом кафе means in this café as a location, so Russian uses the prepositional case after в for static location.

• в этом кафе = in this café
• в это кафе would mean into this café / to this café, showing motion toward it

Also, кафе is an indeclinable noun, so the noun itself stays кафе, but the demonstrative changes:

• nominative: это кафе
• prepositional: в этом кафе

Вам is the dative form of Вы. It is capitalized here to show politeness/formality when addressing one person, similar to a respectful you.

So:

• вам = you (plural, or informal in some contexts)
• Вам = polite/formal you to one person

In many modern texts, people do not always capitalize it, but capitalization is still common in polite written language.

Because подать means to serve or to hand something to someone, and the person receiving something is put in the dative case.

Pattern:

• подать кому? что?
• кому? = dative
• что? = accusative

So here:

• Вам = to you
• сытный салат = a hearty salad

Russian often uses third person plural with no stated subject to mean something like they in a general sense.

So Вам подадут сытный салат literally means:

• They will serve you a hearty salad

But in natural English, we usually translate it more smoothly as:

• You will be served a hearty salad
• They’ll serve you a hearty salad
• This café serves a hearty salad to you is less natural here

This is a very common Russian structure when the specific people are not important.

Because подадут is the future form of the perfective verb подать.

• подавать = imperfective
• подать = perfective
• подадут = they will serve

Russian often uses the perfective future when talking about a single complete action:

• Вам подадут салат = they will serve you a salad

It sounds natural because the sentence refers to what will happen when you order or are served.

Because сытный agrees with салат in gender, number, and case.

• салат is masculine singular
• here it is in the accusative
• for an inanimate masculine noun, the accusative looks like the nominative

So:

• nominative: сытный салат
• accusative: сытный салат

The adjective сытный means something like filling, substantial, or hearty.

Because салат is a masculine inanimate noun, and in Russian, masculine inanimate nouns usually have the same form in the nominative and accusative singular.

So:

• nominative: салат
• accusative: салат

Since подадут takes a direct object, салат is in the accusative, but it happens to look unchanged.

Because в который входят фасоль, кукуруза и петрушка is a relative clause describing салат.

It is like saying:

• a hearty salad, into which beans, corn, and parsley go
• more naturally: a hearty salad, which includes beans, corn, and parsley

Russian normally separates relative clauses with a comma.

Because the verb here is входить в something, meaning to go into, to be included in, or to be part of.

So the structure is:

• что входит во что?
• фасоль входит в салат

When this becomes a relative clause, который has to match салат and keep the preposition required by the verb:

• салат is masculine singular
• direct-object relationship after в here gives в который

So:

• салат, в который входят... = the salad, which includes... / literally the salad, into which ... enter

If you said в котором, that would suggest location in which, but the idiom here is specifically входить в.

Because they are the subject of входят.

Russian sees the ingredients as the things that go into the salad:

• фасоль входит в салат
• кукуруза входит в салат
• петрушка входит в салат

Together:

• фасоль, кукуруза и петрушка входят в салат

So they stay in the nominative, even though in English we often phrase this differently:

• the salad includes beans, corn, and parsley

Because the subject is a list of three things:

• фасоль
• кукуруза
• петрушка

Together they form a plural subject, so the verb is plural:

• входят = enter / are included

If there were only one ingredient, it would be singular:

• В салат входит фасоль.

Literally, входить means to enter or to go into. In this kind of sentence, it means to be included in or to make up part of something.

So:

• в салат входят фасоль, кукуруза и петрушка means
• the salad includes beans, corn, and parsley
• or beans, corn, and parsley are among the ingredients of the salad

This is a very common Russian way to talk about composition.

Фасоль is usually a singular mass/collective noun in Russian when talking about beans as an ingredient.

So:

• в салат входит фасоль = the salad contains beans

Russian often uses singular ingredient nouns where English uses plural:

• фасоль = beans
• кукуруза = corn
• петрушка = parsley

This is normal and does not mean there is only one bean or one piece of parsley.

No. They are different:

• сытный = filling, substantial, hearty
• вкусный = tasty, delicious

A dish can be:

• вкусный, но не сытный = tasty but not filling
• сытный, но не очень вкусный = filling but not very tasty

So сытный салат suggests a salad that is satisfying enough to count as a proper meal or at least a substantial dish.

Yes, several ways are possible. For example:

• В этом кафе Вам подадут сытный салат с фасолью, кукурузой и петрушкой.

  • a hearty salad with beans, corn, and parsley

• В этом кафе Вам подадут сытный салат, который включает фасоль, кукурузу и петрушку.

  • also possible, though в который входят sounds very natural

• В этом кафе подают сытный салат с фасолью, кукурузой и петрушкой.

  • This café serves a hearty salad with beans, corn, and parsley

The original sentence is perfectly natural, but Russian has more than one way to express the same idea.