El pan sale crujiente, pero el puré queda cremoso.

Because this sentence sounds like a general statement about how these foods turn out, not a description of one single past event.

In Spanish, the present tense is very common for:

• general truths
• habitual results
• comments about cooking

So El pan sale crujiente means something like bread comes out crunchy / turns out crunchy in general.

If you were talking about one specific occasion in the past, you would normally say:

• El pan salió crujiente, pero el puré quedó cremoso.

Here, salir does not mean only to leave or to go out. In cooking and everyday Spanish, salir + adjective often means:

• to come out
• to turn out

So el pan sale crujiente means the bread comes out crunchy after baking.

This use is very common for results:

• La tortilla sale muy bien.
• El bizcocho sale esponjoso.

It focuses on the outcome of the process.

Quedar + adjective often means to end up or to be left in a certain state.

So el puré queda cremoso means the purée ends up creamy.

This verb is especially common when talking about:

• texture
• appearance
• final result

For example:

• La salsa queda espesa.
• La carne queda tierna.

It highlights the final state after preparation.

They can sometimes be swapped, but the nuance changes a little.

• El pan sale crujiente sounds very natural because bread literally comes out of the oven with that result.
• El puré queda cremoso sounds very natural because it emphasizes the final texture.

Possible alternatives:

• El pan queda crujiente — possible, but slightly less vivid here
• El puré sale cremoso — also possible in some contexts, but less typical than queda cremoso

So the original sentence sounds idiomatic because each verb fits the food especially well.

Yes, but the meaning focus is different.

• Está crujiente / está cremoso describes the food’s current state
• Sale / queda describes how it turns out after being prepared

Compare:

• El pan está crujiente.
  The bread is crunchy.

• El pan sale crujiente.
  The bread comes out crunchy.

And:

• El puré está cremoso.
  The purée is creamy.

• El puré queda cremoso.
  The purée ends up creamy.

So estar is more descriptive, while salir/quedar are more result-oriented.

Because the subjects are singular:

• el pan
• el puré

So the verbs must be third person singular:

• sale
• queda

If the subjects were plural, the verbs would change:

• Los panes salen crujientes.
• Los purés quedan cremosos.

Because adjectives in Spanish usually agree with the noun they describe.

Here:

• pan is masculine singular
• puré is masculine singular

So the adjectives are also masculine singular:

• crujiente
• cremoso

A useful detail:

• crujiente has the same form in masculine and feminine singular
  
  • pan crujiente
  • masa crujiente
• but the plural changes:
  • crujientes

Cremoso changes more visibly:

• masculine singular: cremoso
• feminine singular: cremosa
• masculine plural: cremosos
• feminine plural: cremosas

Because Spanish often uses the definite article with nouns when talking about something in a general sense.

So:

• El pan sale crujiente
• El puré queda cremoso

sounds natural in Spanish.

In English, we often leave the article out:

• Bread comes out crunchy
• Purée ends up creamy

But Spanish usually prefers the article in this kind of general statement.

Because pero is used to contrast two ideas, and both parts of the sentence are positive statements:

• El pan sale crujiente
• el puré queda cremoso

There is no correction of a negative idea, so pero is the right conjunction.

Use sino when the first part is negative and the second part corrects it:

• El puré no queda espeso, sino cremoso.

So:

• pero = but
• sino = but rather / rather

Because Spanish normally uses a comma before pero when it joins two full clauses, especially when each clause has its own verb.

Here we have:

• El pan sale crujiente
• pero el puré queda cremoso

That comma is standard and natural.

The accent mark shows that the stress falls on the last syllable:

• pu-RÉ

Without the accent, Spanish spelling rules would suggest a different stress pattern.

So the written accent tells you how to pronounce it correctly. It is also the standard spelling of the word:

• puré

Yes. In this sentence, puré is masculine, which is why you get:

• el puré
• cremoso

That is the normal gender for this noun in Spanish. So you would also say:

• un puré bueno
• el puré está caliente