هي محتاجة تنضف البوتاجاز بعد ما الاكل يخلص.

Because the subject is هي meaning she.

• محتاج = masculine singular
• محتاجة = feminine singular

So:

• هو محتاج = he needs
• هي محتاجة = she needs

In Egyptian Arabic, محتاج/محتاجة is very commonly used to express need.

You often can drop هي if the subject is already clear from context.

But محتاجة by itself only tells you the subject is feminine singular. It could mean she, you (feminine), or even I if the speaker is female, depending on context. So هي is useful when you want to make it explicit that the subject is she.

Because after words like محتاج/محتاجة, Egyptian Arabic usually uses the bare imperfect verb.

So:

• هي محتاجة تنضف البوتاجاز = she needs to clean the stove

But:

• هي بتنضف البوتاجاز = she is cleaning / she cleans the stove

The بـ form is usually the regular present/habitual form. After محتاجة, you want the infinitive-like meaning to clean, so تنضف is the normal choice.

In Egyptian Arabic, you normally do not use أن the way you would in Modern Standard Arabic.

So in MSA you might expect something like تحتاج أن تنظف.
But in Egyptian, the natural pattern is simply:

• محتاجة تنضف

This is one of the big differences between spoken Egyptian and formal Arabic.

Here, تنضف means clean.

So تنضف البوتاجاز = clean the stove.

Also, dialect spelling is not fully standardized, so you may see this verb written in different ways in informal Arabic writing, such as تنضف or تنظف. That is normal in colloquial Egyptian writing.

البوتاجاز means the stove or the cooker.

It is a very common Egyptian household word. It is not a classic Arabic-looking word because it is a borrowing, but in everyday Egyptian Arabic it is completely normal.

بعد means after.
When followed by ما, it introduces a whole clause:

• بعد ما الاكل يخلص = after the food is done / after the food finishes

This pattern is extremely common in Egyptian Arabic:

• بعد ما ييجي = after he comes
• بعد ما نخلص = after we finish

So بعد ما is a very useful chunk to learn as after + clause.

Literally, it is something like the food finishes or the food gets done.

In natural English, that usually means:

• after the food is done
• after the cooking is finished
• sometimes after the food is ready

Here, يخلص comes from a very common Egyptian verb meaning finish, be finished, or be done.

In this sentence, it does not usually mean the food runs out.

Because الأكل is treated as a masculine singular noun, so the verb agrees with it:

• الأكل يخلص

If the subject were feminine singular, you would use تخلص instead.

So this is just normal subject-verb agreement.

Yes. بعد ما يخلص الاكل is also understandable and natural.

Both orders can occur in Egyptian Arabic:

• بعد ما الاكل يخلص
• بعد ما يخلص الاكل

The version with الأكل first can feel a little clearer or more topic-first. Word order in spoken Arabic is often flexible, especially in everyday conversation.

Not always.

بعد ما الاكل يخلص often sounds more like:

• after the food is done
• after the cooking is finished

If you specifically want after we finish eating, Egyptian Arabic would often use a different wording, depending on context.

So the exact nuance depends on the situation, but this sentence commonly points to the food being finished/prepared rather than the act of eating being completed.

You could, but the meaning changes a bit.

• هي محتاجة تنضف... = she needs to clean...
• هي لازم تنضف... = she has to / must clean...

لازم sounds stronger, more like obligation.
محتاجة sounds more like there is a need or necessity.

So they are related, but not identical.