Ég er að venjast því að nota meira krydd þegar ég elda pasta.

This is the very common Icelandic pattern vera að + infinitive, which often expresses something in progress, similar to English to be doing.

So:

• ég er að venjast = I am getting used to
• literally, something like I am in the process of getting used to

Without er að, venjast can sound more general or less focused on the ongoing process.

Venjast is the verb that means to get used to or to become accustomed to.

The basic form venja usually means to accustom someone or to make someone used to something, while venjast is the form used when the subject is the one becoming accustomed.

So:

• venja einhvern við eitthvað = to accustom someone to something
• venjast einhverju = to get used to something

In this sentence, ég am the one becoming used to something, so venjast is the right form.

Because venjast normally takes the dative case, and when what follows is an infinitive clause, Icelandic often uses því as a kind of placeholder:

• venjast einhverju = get used to something
• venjast því að gera eitthvað = get used to doing something

So því means something like to it/that, and then að nota meira krydd explains what that it is.

A very literal breakdown would be:

• venjast því = get used to that
• að nota meira krydd = to using more spice

No. Even though því að can be a conjunction meaning because, that is not what is happening in this sentence.

Here the two words have different jobs:

• því belongs to venjast
• að introduces the infinitive nota

So this is:

• venjast því að nota... = get used to using...

not:

• because use...

This is a very common thing for learners to notice, because the same word sequence can mean different things depending on the structure.

They do two different jobs.

1. In er að venjast, að is part of the progressive-style pattern vera að + infinitive.
2. In því að nota, að is the infinitive marker, like English to in to use.

So although they look the same, they are not doing the same thing.

After the infinitive marker að, Icelandic uses the infinitive form of the verb.

So:

• að nota = to use
• að elda = to cook

That is why you see nota here rather than a finite form like notaði, nota, notar, etc.

Because krydd is usually treated as an uncountable or mass noun here, meaning spice/seasoning in a general sense.

In Icelandic:

• meiri/meira/meira is used for more with amounts or uncountable things
• fleiri is used for more with countable plural nouns

So:

• meira krydd = more spice / more seasoning
• fleiri krydd would suggest more spices as separate countable items, which is not the natural meaning here

Also, krydd is a neuter noun, so the form is meira.

It is the direct object of nota, so it is in the accusative.

However, with krydd, the nominative and accusative singular have the same form, so you do not see a visible change.

So even though the case matters grammatically, the word itself stays krydd.

After a conjunction like þegar meaning when, Icelandic usually keeps normal subordinate-clause order:

• þegar ég elda pasta = when I cook pasta

So the subject ég comes before the verb elda.

This is normal Icelandic subordinate-clause structure.

Because the sentence is talking about pasta in a general sense, not a specific already-identified pasta dish.

So:

• elda pasta = cook pasta
• elda pastað = cook the pasta

Using the bare noun is very natural when talking generally about food.

Normally, no. After venjast, Icelandic usually needs því before an infinitive clause.

So the natural pattern is:

• venjast því að gera eitthvað

not:

• venjast að gera eitthvað

That little því is an important part of the construction.

It tells you when the speaker is using more spice.

So the main idea is:

• I am getting used to using more spice

and then the clause

• þegar ég elda pasta

adds the context:

• when I cook pasta

It functions like a time clause modifying the main statement.