Στο παγωτό μού αρέσει το φιστίκι περισσότερο από κάθε άλλη γεύση.

Because αρέσει works more like is pleasing to.

So:

• μού = to me
• αρέσει = pleases
• το φιστίκι = the pistachio / pistachio flavor

The literal structure is roughly:

To me, pistachio is pleasing more than any other flavor.

This is one of the most important patterns in Greek:

• Μου αρέσει το παγωτό. = I like ice cream.
• Μου αρέσουν οι φράουλες. = I like strawberries.

So in Greek, the thing liked is the grammatical subject.

Because the subject is singular: το φιστίκι.

• το φιστίκι = singular, so αρέσει
• If the subject were plural, you would use αρέσουν

Compare:

• Μου αρέσει το φιστίκι. = I like pistachio.
• Μου αρέσουν το φιστίκι και η σοκολάτα. = I like pistachio and chocolate.

The verb agrees with the thing that is pleasing, not with the person who likes it.

Στο παγωτό is σε + το παγωτό, meaning literally in the ice cream or with ice cream, but here it is more naturally understood as:

• when it comes to ice cream
• as far as ice cream is concerned
• in ice cream flavors

So the sentence is setting the context first: among ice cream flavors, pistachio is the one I like most.

This kind of opening phrase is very common in Greek.

Greek uses the definite article much more often than English.

Here το φιστίκι does not necessarily mean one specific pistachio; it can mean the flavor or the general category. Greek often uses the article with foods, flavors, languages, school subjects, and other general nouns.

So:

• το φιστίκι = pistachio / pistachio flavor
• not necessarily the pistachio in a narrow English sense

This is very normal Greek usage.

It can mean either, depending on context.

In this sentence, because of Στο παγωτό and γεύση, it clearly means pistachio flavor.

So although φιστίκι literally means pistachio, the context tells you that we are talking about ice cream flavors, not just the nut by itself.

This is the comparison part:

• περισσότερο = more
• από = than
• κάθε άλλη γεύση = every other flavor / any other flavor

So the whole phrase means: more than any other flavor

It is a natural Greek way to express preference by comparison.

Because άλλη agrees with γεύση.

• γεύση is feminine singular
• so the adjective/pronoun must also be feminine singular: άλλη

Compare agreement:

• κάθε άλλη γεύση = every other flavor
• κάθε άλλος άνθρωπος = every other person
• κάθε άλλο βιβλίο = every other book

Greek agreement is very important: articles, adjectives, and similar words usually match the noun in gender, number, and case.

Because κάθε is normally followed by a singular noun.

So:

• κάθε γεύση = every flavor
• not κάθε γεύσεις

This is like English every flavor, not every flavors.

That is why Greek says: από κάθε άλλη γεύση and not a plural form.

Yes. Greek word order is flexible, although some versions sound more natural in certain contexts.

This sentence starts with Στο παγωτό to establish the topic first. That gives a sense like as for ice cream...

You could also hear things like:

• Το φιστίκι μού αρέσει περισσότερο από κάθε άλλη γεύση στο παγωτό.
• Μου αρέσει περισσότερο το φιστίκι στο παγωτό.

But the original sentence is good because it highlights the category first, then the preference.

You are right: you will very often see μου αρέσει without an accent.

In practice:

• μου is the normal weak form
• μού may appear as a spelling choice by some writers, sometimes to make the rhythm clearer or give a slight emphasis

So for a learner, the important point is:

• μου αρέσει and μού αρέσει mean the same thing here

If you are writing Greek as a learner, μου αρέσει is perfectly standard and safe.

Yes. A very natural alternative would be:

Στο παγωτό προτιμώ το φιστίκι περισσότερο από κάθε άλλη γεύση.

Or more simply:

Στο παγωτό προτιμώ το φιστίκι.

But μου αρέσει and προτιμώ are not exactly identical:

• μου αρέσει = I like
• προτιμώ = I prefer

The original sentence uses μου αρέσει plus a comparison to express something very close to I like pistachio best.