Vi nøjes med rugbrød til aftensmad, hvis køleskabet er tomt.

At nøjes med is a fixed expression meaning to make do with, to settle for, or to be satisfied with.

So in this sentence:

• Vi nøjes med rugbrød = We make do with rye bread / We settle for rye bread

It is not just at nøjes on its own in this meaning; the med is part of the normal pattern. A learner should remember it as one unit:

• at nøjes med noget = to make do with something

Examples:

• Jeg nøjes med kaffe. = I’ll just have coffee.
• De nøjes med et lille værelse. = They make do with a small room.

Because the verb pattern is at nøjes med noget.

That means the thing you are settling for comes after med:

• nøjes med rugbrød
• nøjes med vand
• nøjes med det, vi har

English learners often want to translate word-for-word and expect something like nøjes rugbrød, but Danish requires the preposition med here.

Here rugbrød is being used as an uncountable food noun, like bread in English.

So:

• rugbrød = rye bread, rye-bread as a type of food
• et rugbrød = a loaf of rye bread

In this sentence, the meaning is about what they are eating for dinner in general, not about one specific loaf, so rugbrød without an article is the natural choice.

Compare:

• Vi spiser rugbrød. = We eat rye bread.
• Jeg købte et rugbrød. = I bought a loaf of rye bread.

Til aftensmad means for dinner.

This is a common Danish pattern:

• til morgenmad = for breakfast
• til frokost = for lunch
• til aftensmad = for dinner

Danish normally does not use an article in these expressions. So you say:

• Vi får suppe til aftensmad. = We’re having soup for dinner.

Not:

• til en aftensmad
• til den aftensmad

unless you mean a very specific dinner in a special context.

Køleskabet is the definite form: the fridge.

• et køleskab = a fridge
• køleskabet = the fridge

Danish often uses the definite form when talking about familiar, contextually obvious things—especially things in the home. In English we also usually say the fridge, not a fridge, in a sentence like this.

So:

• hvis køleskabet er tomt = if the fridge is empty

Because køleskab is a neuter noun:

• et køleskab

When an adjective describes a singular neuter noun, it usually takes -t:

• et tomt køleskab = an empty fridge
• køleskabet er tomt = the fridge is empty

Compare with a common-gender noun:

• en tom pose = an empty bag
• posen er tom = the bag is empty

So:

• common gender: tom
• neuter singular: tomt

Because hvis introduces a subordinate clause.

In Danish subordinate clauses, the word order is normally more like English:

• hvis køleskabet er tomt
• because the fridge is empty
• subject + verb

You do not invert the verb and subject after hvis.

That is different from main clauses, where Danish often has verb-second word order. For example:

• Vi nøjes med rugbrød.
• I dag nøjes vi med rugbrød.

But inside the hvis clause:

• hvis køleskabet er tomt

not

• hvis er køleskabet tomt

Yes:

• Hvis køleskabet er tomt, nøjes vi med rugbrød til aftensmad.

This is very natural Danish.

When the subordinate clause comes first, the main clause still follows the Danish verb-second rule, so the verb comes before the subject:

• Hvis køleskabet er tomt, nøjes vi ...

not

• Hvis køleskabet er tomt, vi nøjes ...

That inversion is a very common thing for learners to watch for.

It is grammatically present tense, but Danish present tense often covers:

• a general habit
• a current situation
• a future situation, if the context makes that clear

So this sentence can mean something like:

• We make do with rye bread for dinner if the fridge is empty
• We’ll make do with rye bread for dinner if the fridge is empty

Both are possible depending on context.

This is very similar to English, which also often uses the present tense in if clauses:

• If the fridge is empty, we have rye bread for dinner
• If the fridge is empty, we’ll have rye bread for dinner

Here hvis means if.

It introduces a condition:

• hvis køleskabet er tomt = if the fridge is empty

Danish hvis can sometimes correspond to English whether too, depending on the sentence, but in this example it is clearly conditional.

Examples:

• Jeg ved ikke, om/hvis han kommer. = I don’t know whether he’s coming.
  (Though om is often the more standard choice for whether.)
• Hvis han kommer, starter vi. = If he comes, we’ll start.

So in your sentence, think of hvis simply as if.

A few words here are especially tricky for English speakers:

• nøjes
  The ø is a rounded vowel not found in English. The word is pronounced roughly like NUR-yes / NUR-ice depending on accent, but no English spelling matches it exactly.

• rugbrød
  This is a classic difficult word. The g is not pronounced like a strong English g, and brød contains ø again. Learners often simplify it too much at first.

• køleskabet
  Also contains ø, and the final -et is usually quite unstressed.

If you are learning pronunciation, it is best to learn these by listening rather than from English-style spelling. The vowels ø and the soft Danish consonants are the main challenge.

Because hvis køleskabet er tomt is a subordinate clause.

In written Danish, subordinate clauses are commonly separated with a comma:

• Vi nøjes med rugbrød til aftensmad, hvis køleskabet er tomt.

So the comma marks the boundary between:

• main clause: Vi nøjes med rugbrød til aftensmad
• subordinate clause: hvis køleskabet er tomt

This helps show the structure of the sentence clearly.