Όση δουλειά κι αν έχω, θέλω το βράδυ να μαγειρεύω κάτι απλό, όπως μπρόκολο με κολοκύθι ή ρύζι με γαρίδες.

It is a very common Greek concessive pattern meaning something like no matter how much work I have or however much work I have.

The structure is:

όσος/όση/όσο + noun + κι αν + verb

So here:

• όση = however much / no matter how much
• δουλειά = work
• κι αν έχω = even if I have / no matter that I have

Taken together, the whole clause means:

No matter how much work I have...

Greek often uses this kind of structure where English might use no matter how..., however..., or even if....

Because όση has to agree with δουλειά.

The word όσος changes form like an adjective/pronoun:

• όσος = masculine
• όση = feminine
• όσο = neuter

Since δουλειά is a feminine singular noun, Greek uses όση.

Compare:

• όσο χρόνο κι αν έχω = no matter how much time I have
  (χρόνο is masculine)
• όση υπομονή κι αν έχω = no matter how much patience I have
  (υπομονή is feminine)
• όσο νερό κι αν πίνω = no matter how much water I drink
  (νερό is neuter)

κι is a shortened form of και.

Before a vowel, Greek very often uses κι instead of και, especially in fixed expressions. So:

• κι αν = reduced form of και αν

But in this sentence, κι αν should not be translated word-for-word as simple and if. It is part of the fixed concessive pattern:

όση δουλειά κι αν έχω

which means:

no matter how much work I have

So here κι αν helps create the meaning of concession: even if / no matter whether.

Because Greek treats δουλειά here as an uncountable or mass idea, much like English work.

So όση δουλειά means:

• however much work
• no matter how much work

It does not mean one single job in the literal countable sense. Greek often uses singular nouns this way when talking about an amount of something.

If you wanted to talk about separate jobs/tasks, you might use a different noun, such as δουλειές or εργασίες, depending on context.

In Modern Greek, the subjunctive usually does not have a separate verb form the way it does in some other languages. Very often, the verb form looks the same as the present indicative.

So in:

όση δουλειά κι αν έχω

the important thing is the pattern κι αν + verb, not a special ending on έχω.

In other words:

• the verb form is έχω
• the concessive/subjunctive-like meaning comes from the whole construction

This is normal Modern Greek. You do not need a different present-tense form here.

This is about aspect, one of the most important things in Greek verbs.

• να μαγειρεύω = imperfective aspect
  suggests repetition, habit, or an ongoing activity
• να μαγειρέψω = perfective aspect
  suggests one complete cooking event

Here the sentence includes το βράδυ and describes a general preference or routine:

I want, in the evening, to cook something simple.

So να μαγειρεύω fits because the speaker means something habitual or repeated: in the evenings, I want to be cooking simple things.

If you said να μαγειρέψω, it would sound more like one specific occasion:

I want to cook something simple tonight / on a particular occasion.

Greek often uses the definite article in time expressions where English does not.

So:

• το πρωί = in the morning
• το μεσημέρι = at noon / in the afternoon, depending on context
• το βράδυ = in the evening / at night

This is a very normal adverbial use of the article.

So θέλω το βράδυ να μαγειρεύω... means:

I want to cook... in the evening / at night

Without the article, βράδυ can appear in some expressions, but το βράδυ is the standard form here.

Because κάτι behaves like a neuter word for agreement purposes.

So the adjective also goes in the neuter singular:

• κάτι απλό = something simple
• κάτι καλό = something good
• κάτι μικρό = something small

Even if the thing being referred to might later turn out to be a feminine or masculine noun, after κάτι Greek normally uses the neuter singular adjective.

Here όπως means such as or for example.

So:

κάτι απλό, όπως μπρόκολο με κολοκύθι ή ρύζι με γαρίδες

means:

something simple, such as broccoli with zucchini or rice with shrimp

This use of όπως introduces examples.

It does not mean how here. Greek όπως can have several uses in different contexts, but in this sentence it clearly means such as / like.

Sometimes σαν can also mean like, but όπως is more natural here because the speaker is giving examples.

So:

• όπως μπρόκολο με κολοκύθι... = such as broccoli with zucchini...

This is a clear example-listing use.

σαν is often used more for comparison:

• τρέχει σαν τον άνεμο = he runs like the wind

In a sentence like this one, όπως is the safer and more standard choice.

Because με literally means with, and Greek commonly uses it to name simple dishes or combinations of ingredients.

So:

• μπρόκολο με κολοκύθι = broccoli with zucchini
• ρύζι με γαρίδες = rice with shrimp

This is very natural in food vocabulary. Greek often names dishes by putting one ingredient plus με plus another ingredient.

It does not necessarily mean a formal recipe name; it can just describe a simple meal.

Because the speaker is mentioning foods in a general, non-specific way, as examples of simple things to cook.

So Greek naturally says:

• μπρόκολο με κολοκύθι
• ρύζι με γαρίδες

without articles.

This is similar to English, where we also often say:

• rice with shrimp
• broccoli with zucchini

not the rice with the shrimp, unless we mean a specific dish already known in the conversation.

If the speaker meant specific items, articles could appear:

• το μπρόκολο που αγόρασα
• οι γαρίδες από την αγορά

This is mainly about how the foods are being viewed.

• μπρόκολο, κολοκύθι, and ρύζι are easily used as general ingredient names in the singular.
• γαρίδες is plural because shrimp are usually thought of as multiple individual pieces in a dish.

So:

• ρύζι με γαρίδες sounds natural because a rice dish usually contains several shrimp.
• μπρόκολο με κολοκύθι treats both vegetables as ingredients in a general way.

Greek is flexible with food nouns, but this is a very natural choice.

Yes. The comma separates the opening concessive clause from the main clause.

So the sentence is divided like this:

• Όση δουλειά κι αν έχω, = concessive clause
• θέλω το βράδυ να μαγειρεύω κάτι απλό... = main clause

This is similar to English punctuation in sentences like:

No matter how much work I have, I want to cook something simple in the evening.

The comma helps the reader hear the structure clearly.