Hoy quiero preparar merluza con verduras porque me apetece algo ligero.

Putting hoy first is very natural in Spanish when you want to set the time frame right away.

• Hoy quiero preparar... = Today I want to prepare...

Spanish word order is flexible, so you could also say:

• Quiero preparar merluza con verduras hoy

But starting with hoy sounds smoother here and helps frame the whole sentence from the start.

This is a very common structure in Spanish:

• querer + infinitive

So:

• quiero preparar = I want to prepare

The first verb, quiero, is conjugated. The second verb, preparar, stays in the infinitive.

Other examples:

• Quiero comer = I want to eat
• Quiero descansar = I want to rest

This is exactly like English want to + verb.

Merluza means hake, a very common white fish in Spain.

It is an everyday food word, especially in Spain, where fish is very common in cooking. So this sentence sounds natural and realistic for Peninsular Spanish.

A learner might also notice that merluza is feminine:

• la merluza

But in this sentence, there is no article because it is being used as a food item in a general sense.

In Spanish, when talking about food in a general or indefinite way, it is very common to leave out the article.

So:

• preparar merluza = prepare hake
• comer pescado = eat fish
• hacer arroz = make rice

If you said la merluza, it would usually sound more specific, like a particular hake or a known dish/context.

Here, merluza means the ingredient or type of food in a general sense, so no article is needed.

For the same reason: verduras here is general, not specific.

• con verduras = with vegetables

This means vegetables as part of the dish, not some particular vegetables already known to both speakers.

If you said con las verduras, it would suggest specific vegetables:

• the vegetables we already mentioned
• the vegetables in the kitchen
• the vegetables from some known context

So con verduras is the most natural choice here.

Because here it means because, which in Spanish is porque as one word.

Compare:

• porque = because
• por qué = why

So:

• Hoy quiero preparar merluza con verduras porque me apetece algo ligero.
  = Today I want to prepare hake with vegetables because I feel like something light.

But:

• ¿Por qué quieres preparar merluza?
  = Why do you want to prepare hake?

This is a very common spelling point for learners.

Me apetece means something like:

• I feel like
• I’m in the mood for
• I fancy (especially in British English)

So:

• me apetece algo ligero = I feel like something light

It is a very common and natural expression in Spain.

It often expresses a spontaneous desire or craving, rather than a more general intention.

Compare:

• Quiero comer = I want to eat
• Me apetece comer = I feel like eating

The second one often sounds more like a current mood or appetite.

Because apetecer works like gustar.

The thing that is appealing is the grammatical subject, and the person who feels the desire is expressed with an indirect object pronoun:

• me apetece algo ligero
  • literally: something light appeals to me

So:

• me = to me
• apetece = appeals / is appealing
• algo ligero = something light

That is why Spanish does not normally say yo apetezco for this meaning.

More examples:

• Me apetece café = I feel like coffee
• ¿Te apetece salir? = Do you feel like going out?
• Nos apetece pizza = We feel like pizza

Because the subject is algo ligero, and that is singular.

• Algo ligero me apetece would be a rearranged version of the same structure.
• Since algo is singular, the verb is singular: apetece

If the thing desired were plural, the verb would usually be plural too:

• Me apetecen unas verduras salteadas = I feel like some stir-fried vegetables
• Me apetecen postres = I feel like desserts

So the verb agrees with the thing that is appealing, not with the person.

Algo ligero means something light.

Here, light refers to food that is not heavy, rich, or filling.

So it suggests:

• not too greasy
• not too heavy
• easy to eat

This is a very common phrase in Spanish:

• Quiero cenar algo ligero = I want to have something light for dinner

Because algo is treated as masculine singular for agreement purposes.

So:

• algo ligero
• nada extraño
• mucho bueno is not natural, but the same idea of masculine default often appears with indefinite words

Even if the speaker is talking about food in a general sense, the adjective agrees with algo, not with some implied feminine noun.

So algo ligera would be incorrect here.

Yes, and the combination is very natural.

• Hoy quiero preparar... expresses intention or decision: Today I want to prepare...
• porque me apetece algo ligero explains the reason in terms of mood or appetite: because I feel like something light

So the sentence means:

• I’ve decided / I want to cook this
• and the reason is that I’m in the mood for light food

Using both does not sound repetitive, because they express slightly different ideas.

Yes. That would also be correct, but the nuance changes a little.

• Hoy quiero preparar... = Today I want to prepare...
• Hoy voy a preparar... = Today I’m going to prepare...

Quiero preparar focuses more on desire or intention. Voy a preparar sounds more like a plan or something you are actually going to do.

Both are natural, but quiero preparar fits well with the second half of the sentence, where the speaker gives a personal reason: porque me apetece algo ligero.

It already sounds very natural in Spain Spanish.

A few natural alternatives could be:

• Hoy me apetece preparar merluza con verduras, porque quiero algo ligero.
• Hoy quiero hacer merluza con verduras porque me apetece comer algo ligero.

But the original sentence is completely normal and idiomatic:

• Hoy quiero preparar merluza con verduras porque me apetece algo ligero.

It sounds like something a native speaker in Spain could easily say.