Learn Hardcore Spanish (Spain): Prefiero freír la cebolla con poco aceite. - I prefer to fry the onion with little oil.

The accent marks a hiatus and the stressed syllable: fre-ÍR (two syllables), not one. In Spain it’s pronounced roughly “fre-EER” [fɾeˈiɾ]. Writing it without the accent (freir) is incorrect in standard spelling.

Is freír irregular? Which common forms should I know?

Yes. Key forms:

Present: yo frío, tú fríes, él/ella fríe, nosotros freímos, vosotros freís, ellos fríen.
Gerund: friendo.
Past participles: frito and freído (both are correct; frito is far more common, especially as an adjective: patatas fritas, huevo frito).

Why is it Prefiero freír and not “Prefiero to fry” or “Prefiero a freír”?

In Spanish, preferir is followed directly by a bare infinitive: Prefiero freír. You don’t add a preposition. Use preferir X a Y only when explicitly comparing two options (e.g., Prefiero freír la cebolla a hervirla).

Do I need the personal a before la cebolla?

No. The personal a is used with people (and some pets), not with inanimate objects. Freír la cebolla is the standard direct object construction.

Why la cebolla and not just cebolla? Can it be plural?

la cebolla can refer to a specific onion or to “the onion” as the ingredient in a given context/recipe.
cebolla (no article) is more generic: “onion” as a substance in general (e.g., Prefiero freír cebolla = “I prefer to fry onion” in general).
Use plural when it’s really plural: las cebollas if you mean several onions.

What’s the difference between con poco aceite and con un poco de aceite?

con poco aceite = with very little oil, scarcely any (a more “minimal/insufficient” nuance).
con un poco de aceite = with a bit of oil (neutral “some”). Both are correct; they just differ in nuance.

Is “poco de aceite” (without un) correct?

In this context, you normally say poco aceite or un poco de aceite. The bare “poco de aceite” is not idiomatic here.

Should it be con or en: “freír la cebolla con/en poco aceite”?

Both occur:

freír en (poco) aceite emphasizes the medium (“fry in (a little) oil”), common in recipes.
freír con (poco) aceite emphasizes the resource/amount used (“fry with (a little) oil”). In practice, both are accepted; choose the one that sounds better to you in context.

If I’m just softening onions gently, is freír the best verb in Spain?

Often you’ll hear:

pochar la cebolla = sweat/soften gently until translucent (low heat).
rehogar / sofreír la cebolla = sauté lightly (usually medium heat) to soften and maybe lightly color. Freír is broader and can imply higher heat; for gentle cooking, pochar or rehogar is often more natural.

Where can I place con poco aceite in the sentence?

Spanish is flexible. All of these are fine:

Prefiero freír la cebolla con poco aceite. (default)
Prefiero freír, con poco aceite, la cebolla. (parenthetical emphasis)
Con poco aceite, prefiero freír la cebolla. (fronted for emphasis)
Prefiero freír con poco aceite la cebolla.

How do I replace la cebolla with a pronoun?

Use the feminine direct object pronoun:

Prefiero freírla con poco aceite. (most natural)
La prefiero freír con poco aceite. (also correct, less common) Don’t use lo here; cebolla is feminine.

Does poco agree with the noun? Could it be poca?

Yes, as an adjective it agrees: poco aceite (masc. sing.), poca sal (fem. sing.), pocos carbohidratos, pocas calorías. As an adverb, it doesn’t change: freír poco la cebolla (“not to fry it much”).

How do I say “I prefer to fry the onion rather than boil it”?

Two natural options:

Prefiero freír la cebolla con poco aceite antes que hervirla.
Prefiero freír la cebolla con poco aceite a hervirla.

How do I say “I’d rather you fry the onion with little oil”?

Use preferir que + subjunctive:

Prefiero que frías la cebolla con poco aceite. Here frías is the present subjunctive of freír (note the accent).