La salsa queda mejor con albahaca fresca que con menta.

Here quedar does not mean to stay or to remain. In cooking and similar contexts, quedar often means something like:

• to turn out
• to come out
• to work
• to taste / look / suit something better, depending on context

So La salsa queda mejor con albahaca fresca means the sauce turns out better or works better with fresh basil.

Because quedar focuses on the result or how something comes out.

• es mejor = it is better, more general
• está mejor = it is better now / in its current state
• queda mejor = it turns out better / ends up better / works better in the final result

With food, clothes, decoration, and combinations of ingredients, quedar is very common in Spanish.

Examples:

• Este color queda mejor con negro.
• La tortilla queda mejor con cebolla.

So in this sentence, queda mejor suggests that the sauce is better when prepared or combined with fresh basil.

This is the normal Spanish comparative structure for better ... than ...:

• mejor ... que ... = better ... than ...

So:

• La salsa queda mejor con albahaca fresca que con menta.

literally follows the pattern:

• The sauce turns out better with fresh basil than with mint.

A useful comparison:

• más ... que ... = more ... than ...
• mejor ... que ... = better ... than ...
• peor ... que ... = worse ... than ...

Use que, not de, in this kind of comparison.

Because Spanish normally repeats the preposition in comparisons when each part needs it.

So Spanish says:

• con albahaca fresca que con menta

not:

• con albahaca fresca que menta

The repeated con makes the comparison clear: the sauce is better with basil than with mint.

This is very natural Spanish.

Because when talking about ingredients or substances in a general way, Spanish often leaves out the article after con.

So:

• con albahaca fresca
• con menta

sounds natural when you mean using basil / using mint as ingredients.

If you added the article, it could sound more specific:

• con la albahaca fresca que compré ayer = with the fresh basil I bought yesterday

But in a general ingredient comparison, no article is very normal.

In Spanish, most descriptive adjectives usually come after the noun.

So:

• albahaca fresca = fresh basil
• menta fresca = fresh mint

Putting fresca before the noun would be unusual here and would not sound natural in everyday Spanish.

Post-noun adjective placement is the default, especially for straightforward descriptions like freshness, color, size, etc.

Because it agrees with albahaca, which is a feminine singular noun.

Agreement in Spanish means the adjective must match the noun in:

• gender
• number

So:

• albahaca = feminine singular
• fresca = feminine singular

Compare:

• albahaca fresca
• tomates frescos
• hierbas frescas

This is standard adjective agreement.

Spanish often uses the definite article more than English does.

La salsa can mean:

• the sauce in a specific context
• or sometimes sauce in a general, category-like sense

English often drops the article where Spanish keeps it.

So even if English might say something like Sauce is better with... in some contexts, Spanish naturally says La salsa...

In this sentence, it most likely refers to:

• a particular sauce being discussed, or
• the sauce as a type of dish/preparation

Grammatically, no: fresca only modifies albahaca in the sentence as written.

So the literal comparison is:

• better with fresh basil
• than with mint

It does not explicitly say fresh mint.

If you wanted both to be fresh, you could say:

• La salsa queda mejor con albahaca fresca que con menta fresca.

Sometimes context may make it obvious that both herbs are fresh, but the sentence itself only marks albahaca as fresca.

Yes, but the meaning changes a bit.

• La salsa queda mejor con albahaca fresca que con menta.
  = the sauce turns out / works better with fresh basil

• La salsa sabe mejor con albahaca fresca que con menta.
  = the sauce tastes better with fresh basil than with mint

• La salsa está mejor con albahaca fresca que con menta.
  = less specific; it can mean the sauce is better that way, but it is not as idiomatic for the idea of the final result of a recipe

So queda mejor is especially good when talking about how a combination comes out overall.

Not necessarily. Queda mejor can refer to the overall result, which may include:

• taste
• balance
• suitability
• even appearance, depending on context

In a food sentence like this, taste is probably the main idea, but queda mejor is slightly broader than simply sabe mejor.

That is why it is a very natural choice here.