Yo prefiero los calamares a la plancha, aunque mi madre dice que el pulpo está mejor con patata.

Yes — Spanish often drops subject pronouns because the verb already shows who is doing the action. So Prefiero los calamares... would be perfectly natural.

Using yo here adds a bit of emphasis or contrast, as if the speaker is saying:

• As for me, I prefer...
• I prefer..., although my mother says...

So yo is not required, but it helps highlight the speaker’s personal opinion.

Because preferir is a stem-changing verb.

In the present tense, the e in the stem changes to ie in most forms:

• yo prefiero
• tú prefieres
• él/ella prefiere
• nosotros preferimos
• vosotros preferís
• ellos prefieren

So prefiero is the correct yo form.

Spanish very often uses the definite article with food, animals, and things when talking about them in a general sense.

So:

• prefiero los calamares
• me gusta el café
• odio las cebollas

This is very natural in Spanish. English usually leaves the article out in these cases, but Spanish often keeps it.

Both are possible in Spanish, depending on how the speaker is thinking about the food.

Here, los calamares sounds like squid dishes / squid in general, while el pulpo sounds like octopus as a dish / octopus in general.

Spanish can talk about food either:

• in the plural: los calamares, las sardinas
• in the singular with an article: el pulpo, el salmón

So this mix is not strange. It is just two natural ways of referring to food.

A la plancha is a fixed cooking expression. It means something like:

• grilled on a flat hot plate
• cooked on a griddle

It is extremely common in Spain for fish, seafood, meat, and vegetables.

Examples:

• sepia a la plancha
• pollo a la plancha
• verduras a la plancha

So you should learn a la plancha as a set phrase, not word by word.

Aunque means although / even though.

It introduces a contrast:

• I prefer squid..., although my mother says...

A useful grammar point is that aunque can be followed by either the indicative or the subjunctive, depending on meaning.

Here it takes the indicative:

• aunque mi madre dice...

That is because the speaker is referring to a real, known fact: the mother actually says this.

Compare:

• Aunque está caro, lo compro. = Even though it’s expensive, I’m buying it.
• Aunque esté caro, lo compraré. = Even if it’s expensive, I’ll buy it.

Because decir que is the normal structure for reporting what someone says.

• Mi madre dice que...
• He says that...

In English, that is often optional:

• My mother says that...
• My mother says...

In Spanish, que is normally required in this kind of sentence.

This is a very common ser vs estar question.

Here, está mejor means something like:

• tastes better
• is better that way
• is nicer served like that

Estar is used because the speaker is talking about how the dish turns out, how it is served, or how it seems in that situation — not about an essential, permanent characteristic.

So:

• El pulpo está mejor con patata = Octopus is better with potato / tastes better with potato.

If you said es mejor, it could sound more like a general judgment or abstract comparison. In food contexts, está mejor is very natural for taste and preparation.

Because in Spanish, an ingredient can be mentioned in the singular as a kind of mass or category noun.

So con patata can mean:

• with potato
• with some potato
• with potato as an accompaniment

This is similar to how English sometimes uses singular ingredient words, like with cheese or with onion.

That said, con patatas is also possible in other contexts, especially if you are thinking of actual separate potatoes or pieces of potato. The singular here sounds like the ingredient or style of serving, which is very natural.

Because when Spanish names an ingredient or accompaniment in a general way, it often leaves out the article.

So:

• con patata
• con arroz
• con cebolla
• con queso

This makes it sound like the food is served with potato / rice / onion / cheese as an ingredient or side, rather than referring to a specific potato.

Absolutely. A very natural version would be:

• Prefiero los calamares a la plancha, aunque mi madre dice que el pulpo está mejor con patata.

That is probably what you would hear most often in everyday speech unless the speaker wants emphasis.

So the difference is roughly:

• Prefiero... = neutral
• Yo prefiero... = slightly emphatic, personal, or contrastive

Yes, it sounds very natural for Spain.

A few things help give it that feel:

• a la plancha is extremely common in Spain
• seafood like calamares and pulpo are very common food words there
• está mejor con patata sounds like a natural opinion about how a dish is best served

So this is a good example of everyday, idiomatic Spanish from Spain, especially in a food context.