Ne égesd oda a gombát!

Because ne is the negative particle used with commands, requests, and other imperative/subjunctive forms.

• nem negates ordinary statements: Nem égeted oda a gombát. = You are not burning the mushroom.
• ne negates a command: Ne égesd oda a gombát! = Don’t burn the mushroom.

So in English you use don’t, but in Hungarian that idea is built with ne + an imperative/subjunctive verb form.

Égesd is the 2nd person singular imperative/subjunctive form of éget(ni), here used as part of odaéget(ni).

So the basic idea is:

• éget = burns something, scorches something
• odaéget = burns something onto a surface / lets it get stuck by burning

In this sentence, égesd means burn it in the command form, and with ne it becomes don’t burn it.

That -d shows the definite conjugation in the 2nd person singular imperative.

Hungarian verbs often change depending on whether the direct object is definite or indefinite. Here the object is a gombát = the mushroom, which is definite, so the verb uses the definite form.

Compare:

• Ne égess gombát! = Don’t burn mushrooms / don’t burn any mushroom.
  indefinite object
• Ne égesd a gombát! = Don’t burn the mushroom.
  definite object

This is one of the things that often surprises English speakers, because English verbs do not change this way.

This is because Hungarian imperative forms are not always made by simply adding an ending to the basic present-tense form.

With verbs like éget, the imperative stem changes:

• éget
• imperative stem: égess-
• 2nd person singular definite imperative: égesd

This kind of change is normal in Hungarian. Similar patterns happen with other verbs too:

• mutat → mutass
• fizet → fizess

So égesd is not random; it follows an established imperative pattern.

By itself, oda usually means there / to that place / over there, but here it is a verbal prefix.

With éget, it gives the idea of:

• burning something onto a surface
• scorching it so that it sticks
• overcooking it in a bad way

So odaégetni is stronger and more specific than just égetni. In cooking, it often means something like burn it onto the pan or scorch it badly.

Because verbal prefixes in Hungarian often separate from the verb in commands and under negation.

So:

• neutral statement: Odaégeted a gombát. = You burn the mushroom onto it / You scorch the mushroom.
• negative command: Ne égesd oda a gombát!

This is a very common Hungarian pattern. Compare:

• leteszi = puts it down
• Tedd le! = Put it down!
• Ne tedd le! = Don’t put it down!

So oda is after égesd because this is a negative imperative.

The -t marks the accusative case, which is the case of the direct object.

• gomba = mushroom
• gombát = mushroom as the thing being acted on

Since the mushroom is what is being burned, Hungarian marks it with -t.

So:

• a gomba = the mushroom
• a gombát = the mushroom, as the direct object

It is singular.

• gomba = mushroom
• gombát = mushroom (accusative singular)
• gombákat = mushrooms (accusative plural)

So grammatically this sentence refers to the mushroom in the singular. In real cooking contexts, Hungarian sometimes uses the singular where English might prefer a plural or a mass-style translation, but the form itself here is definitely singular.

This is a very useful distinction:

• ég = to burn, be burning
  intransitive
• éget = to burn something, scorch something
  transitive
• odaég = to burn onto something, get scorched and stick
  intransitive
• odaéget = to burn something onto something, make it stick by burning
  transitive

Examples:

• A gomba odaég. = The mushroom gets burnt onto the pan.
• Odaégeted a gombát. = You burn the mushroom onto the pan.

English often uses burn for both ideas, but Hungarian distinguishes whether the action happens by itself or whether someone does it to something.

Yes, but the emphasis changes.

The basic version is:

• Ne égesd oda a gombát!

Other possible orders include:

• A gombát ne égesd oda!
  This puts more emphasis on the mushroom.
• Ne a gombát égesd oda!
  This is contrastive, roughly Don’t burn the mushroom; burn something else instead or It’s not the mushroom that should get burnt.

So Hungarian word order is flexible, but it is not free in the sense of meaning nothing. Different orders usually signal different focus or emphasis.

The sentence as given is informal singular, said to one person you address as te.

Other versions:

• Ne égesse oda a gombát! = polite singular / formal
• Ne égessétek oda a gombát! = informal plural
• Ne égessék oda a gombát! = polite plural / formal plural

So the form of the verb changes depending on who you are talking to.