A mi abuela no le gusta el chocolate demasiado amargo, pero sí el yogur cremoso con miel.

Spanish often uses gustar differently from English to like.

Literally, gustar works more like to be pleasing to. So:

• A mi abuela le gusta el chocolate demasiado amargo
  = Overly bitter chocolate is pleasing to my grandmother
  = My grandmother likes overly bitter chocolate / in this sentence, with no, doesn’t like

That is why the person who experiences the liking is introduced with a and also appears as an indirect object pronoun: le.

Yes, they both point to the same person, and that is normal in Spanish.

This is called clitic doubling. The pronoun le is usually required with gustar, and a mi abuela adds clarity or emphasis.

So:

• Le gusta... = She likes...
• A mi abuela le gusta... = My grandmother likes...

You usually keep both, especially when naming the person directly.

Because with gustar, the person is not the grammatical subject. The thing liked is the grammatical subject, and the person is treated as an indirect object.

So Spanish marks that person with a:

• A mi abuela le gusta el yogur
• literally: To my grandmother, the yogurt is pleasing

If you said just mi abuela gusta..., that would be incorrect here.

Because the grammatical subject is singular in each clause:

• el chocolate demasiado amargo = singular
• el yogur cremoso con miel = singular

So you use gusta.

Compare:

• Le gusta el chocolate = She likes chocolate
• Le gustan los chocolates = She likes the chocolates / chocolates

A useful rule: with gustar, match the verb to the thing liked, not to the person who likes it.

Spanish often uses the definite article with nouns when speaking about things in a general sense.

So:

• me gusta el chocolate
• le gusta el yogur

This is very natural in Spanish, even though English usually says just chocolate or yogurt without the.

Here, demasiado means too or overly, and it modifies the adjective amargo.

So:

• amargo = bitter
• demasiado amargo = too bitter / overly bitter

It does not mean very bitter.
For very bitter, you would say muy amargo.

In Spanish, descriptive adjectives usually come after the noun.

So:

• el chocolate amargo
• el yogur cremoso

That is the normal order. Adjectives can sometimes come before the noun, but that often changes the tone, emphasis, or meaning. In this sentence, the standard post-noun position is the natural choice.

Pero sí creates a strong contrast:

• no le gusta X, pero sí Y
• she doesn’t like X, but she does like Y

Here it means:

• she does not like overly bitter chocolate,
• but she does like creamy yogurt with honey.

The sí is emphatic. It contrasts with the earlier no.

Because sí with an accent means yes or adds emphatic affirmation, as it does here.

Without the accent, si usually means if.

So:

• sí = yes / indeed / does
• si = if

In pero sí el yogur cremoso con miel, the accent is necessary.

Spanish often leaves out repeated words when the meaning is clear.

So:

• A mi abuela no le gusta el chocolate demasiado amargo, pero sí el yogur cremoso con miel

is a shortened version of:

• A mi abuela no le gusta el chocolate demasiado amargo, pero sí le gusta el yogur cremoso con miel

Both are correct, but the shorter version sounds more natural because it avoids repetition.

Con miel means with honey: yogurt served together with honey or topped with honey.

• yogur cremoso con miel = creamy yogurt with honey

If you said de miel, it would more likely suggest something like honey-flavored or made of honey, depending on context. That is a different idea.

Yes. In Spain, yogur is a very common standard spelling, and it is masculine:

• el yogur

You may also see yogurt, and people will understand it, but yogur is very common in Spain and fits the style of this sentence well.

Yes, you can change the word order, but the meaning and emphasis change a little.

For example:

• A mi abuela no le gusta...
  This is very natural and neutral. It sets up my grandmother as the topic.

• No le gusta... a mi abuela
  This is possible, but it sounds more marked and less neutral in many contexts.

Starting with A mi abuela is a very common and natural way to frame the sentence.