În bucătărie este un miros bun de pâine caldă.

After prepositions, Romanian often uses the noun without the definite article when talking about a general, familiar location such as in the kitchen, at school, in bed, and so on.

So în bucătărie is the normal way to say in the kitchen.

You are more likely to see the definite article if the noun is further specified, for example:

• în bucătăria casei = in the kitchen of the house
• în bucătăria mea = in my kitchen

Romanian often expresses existence with just este or e plus the noun.

So:

• Este un miros... literally looks like is a smell...
• but it means there is a smell...

When a place is mentioned first, Romanian often puts it at the beginning:

• În bucătărie este un miros... = In the kitchen, there is a smell...

This is a very common Romanian pattern.

Because miros is a singular countable noun here, and Romanian normally uses the indefinite article when introducing one unspecified thing:

• un miros = a smell

Just like English says a smell, Romanian says un miros.

In Romanian, adjectives usually come after the noun they describe.

So:

• miros bun = good / pleasant smell
• pâine caldă = warm bread

This is the normal word order. An adjective can sometimes come before the noun, but that is less neutral and often adds emphasis or a more literary tone.

Here bun means something like pleasant, nice, or good-smelling, not morally good.

Romanian uses bun in a wide range of ways, and the exact English translation depends on context.

So un miros bun is best understood as:

• a nice smell
• a pleasant smell

Here de introduces what kind of smell it is or what it smells like.

So:

• miros de pâine caldă = smell of warm bread

In this structure, de is very common with nouns like miros:

• miros de cafea = smell of coffee
• miros de flori = smell of flowers
• miros de fum = smell of smoke

Because caldă agrees with pâine, and pâine is feminine singular.

Romanian adjectives must agree with the noun in gender and number.

So:

• pâine = feminine singular
• caldă = feminine singular form of warm

Compare:

• pâine caldă = warm bread
• vin cald = warm wine
  because vin is masculine/neuter singular

Because after de, Romanian often uses a bare noun when naming a substance, category, or type in expressions like this.

So:

• miros de pâine caldă = a smell of warm bread / the smell of warm bread

This is a general descriptive phrase, not a reference to one specific loaf already identified.

If you wanted a more specifically definite idea, Romanian would structure it differently, for example:

• mirosul pâinii calde = the smell of the warm bread

That is a more definite and more tightly linked structure.

Because the subject is singular:

• un miros = a smell

So the verb must also be singular:

• este un miros

If the subject were plural, then you would use sunt:

• În bucătărie sunt niște mirosuri ciudate = There are some strange smells in the kitchen

Yes. Romanian word order is fairly flexible, especially with location phrases.

This sentence starts with În bucătărie to set the scene first. That is very natural.

Other possible orders include:

• Este un miros bun de pâine caldă în bucătărie.
• Un miros bun de pâine caldă este în bucătărie.
  This last one is much less natural in ordinary speech.

So the original order is good because it sounds like: first the place, then what is there.

It is understandable and grammatical, but many native speakers would more naturally say:

• În bucătărie miroase a pâine caldă. = It smells like warm bread in the kitchen.
• În bucătărie este un miros plăcut de pâine caldă. = There is a pleasant smell of warm bread in the kitchen.

Your sentence is fine, but miroase a... is often the more everyday way to talk about smells.

They are related, but the grammar is different:

• miros de pâine caldă is a noun phrase: a smell of warm bread
• miroase a pâine caldă is a verb phrase: it smells like warm bread

So:

• Este un miros de pâine caldă focuses on the existence of the smell
• Miroase a pâine caldă focuses on the sensory impression

Both are common, but the second one is often more idiomatic in everyday speech.