Ako luk narežeš tanje, brže će se ispeći.

Because after ako (if), Croatian normally uses a finite verb form, not the infinitive.

So:

• Ako luk narežeš... = If you slice the onion...
• narežeš = you slice / you will slice in this kind of conditional sentence

The infinitive narezati would not work here, because Croatian needs a fully conjugated verb after ako.

This is very common in Croatian. After ako (if), Croatian often uses the present tense to talk about a future condition.

So:

• Ako luk narežeš tanje... literally looks like If you slice the onion thinner...
• but the meaning is really If you slice the onion thinner (in the future), it will cook faster

English often does something similar:

• If you cut it thinner, it will cook faster

So the Croatian present here does not mean present-time action only; it can express a future condition.

narežeš comes from the perfective verb narezati / narežem, narežeš..., which means to slice up / cut into pieces as a completed action.

Croatian often uses a perfective present after ako when talking about a future completed action:

• Ako luk narežeš... = If you slice the onion... / If you have sliced the onion...

The idea is that the cutting is treated as a completed step before the next result happens.

By contrast, an imperfective verb would focus more on the process or repeated action.

Croatian often omits subject pronouns when they are already clear from the verb ending.

Here, narežeš already tells us the subject is you (singular).

So:

• narežeš = you slice
• adding ti is possible, but usually unnecessary unless you want emphasis or contrast

For example:

• Ako ti luk narežeš tanje... would sound marked and would usually suggest emphasis, like if you slice the onion thinner...

Normally, just narežeš is enough.

Because luk here is the direct object, and for a masculine inanimate noun like luk (onion), the accusative singular is the same as the nominative singular.

So:

• nominative: luk
• accusative: luk

That is why you see:

• narežeš luk = you slice the onion

If it were a masculine animate noun, the accusative would usually look different.

Tanje means more thinly or thinner.

It is the comparative form used adverbially here. In natural English, we usually say:

• slice it thinner
• cut it more thinly

In Croatian, this comes from the adjective tanak (thin), but in this sentence it functions as an adverb describing how you slice the onion.

So:

• narežeš tanje = slice it thinner

Because tanje is not describing the noun luk directly. It is describing the manner of the action narežeš.

Compare:

• tanji luk = a thinner onion → adjective describing the noun
• narežeš luk tanje = you slice the onion thinner → adverb-like use describing how the slicing is done

So here tanje does not need to match luk in gender, number, or case.

Brže means faster / more quickly. It is the comparative of brzo (quickly / fast).

It describes how the onion will cook:

• brže će se ispeći = it will cook faster

So the sentence has two comparatives:

• tanje = thinner
• brže = faster

This creates the cause-and-effect relationship:

• cut it thinner → it cooks faster

Će se ispeći means will cook through / will get baked-roasted / will be done.

Breakdown:

• će = future auxiliary (will)
• se = reflexive particle
• ispeći = perfective infinitive meaning to bake/roast/cook through completely

Together:

• će se ispeći = it will get cooked / it will cook through

Depending on context, English may translate this as:

• will cook faster
• will bake faster
• will roast faster
• will be done faster

Here se is part of the verb expression. In many Croatian verbs, se helps form a meaning that is often natural in English as something like:

• cook
• get cooked
• become cooked

So:

• ispeći can be transitive: to bake/roast something
• ispeći se often means to bake/roast/cook through itself / become baked

In this sentence, the onion is not the doer in an active English sense, but Croatian naturally says:

• luk će se ispeći = the onion will cook / will get cooked

This is a very common pattern in Croatian.

This is because će and se are both clitics, and Croatian has rules about their placement.

In a simple clause, clitics usually come in the second position of the clause.

So in:

• brže će se ispeći

the first stressed element is brže, and then the clitic sequence follows:

• će se

After that comes the main verb:

• ispeći

So brže će se ispeći is the normal order.

Yes. Croatian word order is fairly flexible, and several versions are possible:

• Ako luk narežeš tanje...
• Ako narežeš luk tanje...

Both are understandable and natural. The difference is mostly about emphasis and information flow.

• Ako luk narežeš tanje... puts luk earlier, so the onion is introduced immediately
• Ako narežeš luk tanje... puts the verb earlier, which can sound a bit more neutral in some contexts

Croatian often changes word order for style, focus, or rhythm rather than for basic grammar.

This is an aspect difference.

• peći = imperfective → to bake/roast/cook, focusing on the process
• ispeći = perfective → to bake/roast/cook completely, focusing on the completed result

In this sentence, the result matters: the onion will end up cooked sooner. That is why ispeći is used.

So:

• brže će se peći would focus more on the ongoing cooking process
• brže će se ispeći focuses on becoming done faster

Literally, ispeći se is connected with baking/roasting. But in real translation, the best English word depends on context.

In a cooking context, it may be rendered as:

• cook faster
• bake faster
• roast faster

If the wider context is not specific, cook faster is often the most natural English translation.

So the Croatian verb is a bit more specific than the most general English translation may be.

Yes. It can express a general, practical fact:

• If you slice the onion thinner, it will cook faster

Croatian often uses this structure for instructions, recipes, and general cause-and-effect statements.

So it is not only about one single future event. It can also mean something like:

• Whenever onion is sliced thinner, it cooks faster
• As a rule, thinner slices cook faster

The exact reading depends on context, but the sentence works very naturally as a general cooking tip.