Las natillas de mi tía siempre salen muy cremosas.

In Spanish, las natillas is very commonly used in the plural to refer to the dessert as a dish, even when you are talking about it in a general sense.

So:

• las natillas = custard / custards / the dessert called custard

This is one of those cases where Spanish and English package the idea differently. English often uses an uncountable noun like custard, but Spanish often uses the plural natillas.

You may also hear singular natilla in some contexts, but natillas is the normal everyday word for the dessert.

Yes, salir often means to go out, to leave, or to come out, but it also has another very common meaning in cooking and results:

• salir bien/mal = to turn out well/badly
• salir rico = to turn out tasty
• salir cremoso = to turn out creamy

So in this sentence, salen muy cremosas means:

• they always turn out very creamy

This use of salir is especially common when talking about how food, plans, photos, or results end up.

Examples:

• La tortilla me sale bien. = My omelette turns out well.
• Las fotos salieron borrosas. = The photos came out blurry.

Because the subject is Las natillas, which is plural.

• La natilla sale... = The custard turns out...
• Las natillas salen... = The custards / the custard turns out...

The verb has to agree with the subject:

• las natillas → plural
• salen → 3rd person plural

Because cremosas is an adjective describing las natillas, and Spanish adjectives must agree with the noun in gender and number.

• natillas is feminine plural
• so the adjective must also be feminine plural: cremosas

Compare:

• el flan cremoso = the creamy flan
• la crema cremosa = the creamy cream
• las natillas cremosas = the creamy custards

Spanish does not use an apostrophe-s possession structure like English. Instead, it usually uses:

• noun + de + person

So:

• las natillas de mi tía = my aunt’s custard

Literally, this is more like:

• the custard of my aunt

This de structure is extremely common in Spanish:

• el coche de mi hermano = my brother’s car
• la casa de Ana = Ana’s house

In Spanish, possessive words like mi, tu, su, nuestro usually replace the article.

So you normally say:

• mi tía = my aunt
• not la mi tía

That means de mi tía is the normal form.

You do sometimes see article + possessive in older, literary, or regional language, but not in standard everyday Spanish here.

Siempre usually goes before the verb, but Spanish word order is fairly flexible.

In this sentence:

• Las natillas de mi tía siempre salen muy cremosas.

This is the most natural, neutral order.

You could also hear:

• Las natillas de mi tía salen siempre muy cremosas.

That is possible, though a bit less neutral in many contexts. Placing siempre before the verb is the most common choice.

Because salir focuses on the result: how something turns out after being made.

• son muy cremosas would describe them as generally being creamy by nature
• están muy cremosas would describe their current state
• salen muy cremosas means they come out / turn out very creamy when your aunt makes them

So salir is the best choice when you are talking about the outcome of cooking.

Mostly yes. Muy means very and goes before adjectives and adverbs.

Here:

• muy cremosas = very creamy

Examples:

• muy bueno = very good
• muy rápido = very fast
• muy bien = very well

One thing to remember: Spanish uses muy, not mucho, before adjectives.

So:

• muy cremosas = correct
• mucho cremosas = incorrect

Yes. The full subject is:

• Las natillas de mi tía

That whole noun phrase is what salen refers to.

Breakdown:

• Las natillas = the custard
• de mi tía = of my aunt / my aunt’s

So the sentence structure is basically:

• [Subject] Las natillas de mi tía
• [Adverb] siempre
• [Verb] salen
• [Complement] muy cremosas

Yes, grammatically it could. But in normal use, las natillas often refers to the dessert as a whole rather than emphasizing separate individual custards.

So depending on context, it could suggest:

• the dessert in general
• the batches she makes
• the portions/servings

In most everyday situations, a Spanish speaker would simply understand it as my aunt’s custard always turns out very creamy.

Yes, it sounds natural in Spain.

A very natural interpretation is:

• your aunt makes natillas
• whenever she makes them, they turn out very creamy

This is exactly the kind of sentence where salir is especially idiomatic in Spanish cooking talk.

Yes. That is also natural, and it uses a very common Spanish structure with indirect object + salir:

• A mi tía le salen muy cremosas las natillas.

This literally works like:

• To my aunt, the custards turn out very creamy

In more natural English:

• My aunt’s custard always turns out very creamy.

Both versions are good, but they focus slightly differently:

• Las natillas de mi tía siempre salen... focuses on the custard
• A mi tía le salen... focuses more on your aunt as the person getting that result

Usually natillas refers to the traditional Spanish-style custard dessert, often flavored with vanilla, cinnamon, or lemon. In many contexts, though, learners can think of it broadly as custard.

So the word is both:

• a specific familiar dessert in Spain
• a useful translation for custard in many food contexts

The exact meaning depends on context, but in a sentence like this, it strongly suggests the Spanish dessert.