A la ensalada le pongo perejil fresco y un poco de orégano.

Yes, both refer to the same thing, and this is very common in Spanish.

• a la ensalada names the recipient clearly.
• le repeats that idea as an indirect object pronoun.

This is called clitic doubling, and Spanish uses it a lot, especially with indirect objects.

So:

• A la ensalada le pongo perejil...
• Le pongo perejil a la ensalada.

Both are natural. In English we usually would not repeat it, but in Spanish this repetition is normal.

Because Spanish is treating the salad as the thing that receives the ingredient, not just the place where it ends up.

• A la ensalada le pongo... = I add/put ... to the salad.
• En la ensalada pongo... = I put ... in the salad.

Both can be possible in some contexts, but a la ensalada le pongo... is a very natural way to talk about adding ingredients to a dish. It sounds more like the salad gets parsley and oregano.

Pongo is the first person singular present form of poner.

So:

• poner = to put
• pongo = I put / I add

This is an irregular verb, so it is not pono.

Other forms:

• pongo = I put
• pones = you put
• pone = he/she puts

In recipes or when describing how you usually prepare something, the present tense often sounds natural in Spanish.

Here it often feels closer to to add in natural English.

In cooking Spanish, poner is used very broadly. It can mean:

• to put
• to add
• to include

So A la ensalada le pongo perejil fresco... is something like I add fresh parsley to the salad.

It is a very everyday, idiomatic verb in this kind of context.

Yes, both are possible, but the nuance changes a bit.

• echo from echar: very common in everyday cooking Spanish; often means I throw in / I add
• añado from añadir: more explicitly I add
• pongo from poner: very common, simple, and natural

Examples:

• A la ensalada le echo perejil fresco...
• A la ensalada le añado perejil fresco...
• A la ensalada le pongo perejil fresco...

All three can work. Pongo is especially common and neutral.

Spanish usually uses the definite article more often than English.

Here la ensalada means the salad, usually the specific salad being prepared or discussed.

Even where English might sometimes say I add parsley to salad, Spanish normally prefers a la ensalada rather than dropping the article.

Also, a + la = a la.
There is no special contraction here beyond that; it just stays a la because ensalada is feminine.

Because when talking about ingredients or substances in a general, non-counted way, Spanish often uses no article.

So:

• pongo perejil fresco = I add fresh parsley
• compro pan = I buy bread
• bebo agua = I drink water

If you added an article, it would usually sound more specific:

• pongo el perejil fresco = I add the fresh parsley

That would suggest a particular parsley already known in the conversation.

Because un poco de is the normal structure.

After quantity expressions like these, Spanish uses de:

• un poco de orégano
• mucho azúcar
• un vaso de agua
• una pizca de sal

So un poco de + noun = a little bit of + noun.

You need the de here.

Because in Spanish, descriptive adjectives often come after the noun.

So:

• perejil fresco = fresh parsley
• pan caliente = hot bread
• vino tinto = red wine

Putting fresco after the noun is the most normal order here.

If an adjective goes before the noun, it often adds a different tone or emphasis, but fresco perejil would not sound natural here.

Because le is the indirect object pronoun.

In this sentence, the salad is the thing receiving the parsley and oregano, so Spanish treats it as an indirect object:

• le = to it / to her / to him

La would be a direct object pronoun, and that is not the role here.

So:

• Le pongo perejil a la ensalada = correct
• La pongo perejil = not correct for this meaning

Yes. Spanish word order is flexible, and these are all natural:

• A la ensalada le pongo perejil fresco y un poco de orégano.
• Le pongo perejil fresco y un poco de orégano a la ensalada.
• Pongo perejil fresco y un poco de orégano a la ensalada.

The version with both a la ensalada and le sounds especially natural and conversational.

Starting with A la ensalada can help set the topic first, like As for the salad...

It can be either, depending on context.

The Spanish present tense often covers both:

• what I usually do
• what I’m doing now
• how I make it in general

So this sentence could mean:

• I put fresh parsley and a little oregano in the salad as a habit
• or I’m putting fresh parsley and a little oregano in the salad right now

Context tells you which one is meant.

Because the stress falls on the second syllable: o-RÉ-ga-no.

The written accent shows the correct stress. Without it, Spanish pronunciation rules would suggest a different stress pattern.

So it should be written:

• orégano

not

• oregano

Yes, it sounds very natural in Spain.

A speaker in Spain would easily say:

• A la ensalada le pongo...
• Le echo...
• Le añado...

All of these are normal in everyday cooking language. The sentence you have is completely natural and idiomatic for Spain.