La crema de verduras queda suave con un poco de leche.

Because the subject is la crema, which is singular. The phrase de verduras only tells you what kind of cream it is; it does not change the number of the subject.

So the structure is:

• La crema = subject
• queda = 3rd person singular verb
• suave = description of the result

If the subject were plural, the verb would also be plural:

• Las cremas de verduras quedan suaves...

Here, quedar means something like to turn out, to end up, or to come out in a certain state.

It is very common in Spanish when talking about the result of food, recipes, clothes, or any final outcome.

So queda suave means the cream ends up smooth / comes out smooth / turns out smooth.

This is different from simply describing it. Quedar focuses on the result.

Because suave is an adjective, and after quedar you normally use an adjective to describe the subject.

• La crema queda suave. = The cream turns out smooth.

Suavemente is an adverb, and adverbs describe how an action is done, not what something is like.

Compare:

• La crema queda suave. → describes the cream
• Mezcla suavemente. → describes how you mix

So after quedar, suave is the correct choice.

Yes, but the meaning changes slightly.

• queda suave = it turns out smooth, or ends up smooth
• está suave = it is smooth

So queda emphasizes the result, especially after adding the milk.
Está just describes the current state.

In a cooking context, queda suave is very natural because you are talking about how the soup turns out.

Because de is commonly used to name what a dish is made from or what type it is.

So:

• crema de verduras = vegetable cream / cream of vegetables
• sopa de pollo = chicken soup
• jugo de naranja = orange juice

If you said con verduras, that would suggest something more like with vegetables added rather than a vegetable-based cream.

So de verduras identifies the kind of dish.

Because crema de verduras usually refers to a cream made from mixed vegetables, not just one vegetable.

In Spanish, the plural often sounds natural when talking about assorted vegetables used together in a dish.

• crema de verduras = a cream made from various vegetables

You may also see verdura in other contexts, because verdura can work as a collective noun, but crema de verduras is a very common fixed expression.

Un poco de leche means a little milk in a neutral, positive way. It suggests that this small amount helps the cream become smooth.

Poca leche means little milk / not much milk, and it can sound more like you are emphasizing a small or insufficient quantity.

So:

• con un poco de leche = with a little milk
• con poca leche = with little milk

In this sentence, un poco de leche sounds more natural because it presents the milk as a helpful addition.

Because after quantity expressions like un poco de, Spanish normally uses de + noun without an article.

So you say:

• un poco de leche
• un vaso de agua
• mucho pan

You would only use an article if you meant a specific milk already known in the context:

• un poco de la leche que compraste ayer

But in the sentence, leche is being used in a general, non-specific way, so no article is needed.

It can suggest either one depending on context, but with crema de verduras, it often refers mainly to the texture being smooth, soft, or not harsh.

It can also imply the flavor is mild rather than strong.

So in a food context, suave often has a broad, pleasant meaning:

• smooth in texture
• mild in flavor
• gentle, not intense

That is why it works well here.

Yes, Spanish allows some flexibility in word order.

For example, you could say:

• Con un poco de leche, la crema de verduras queda suave.

This still sounds natural.

However, the original order is very normal because it flows well:

• La crema de verduras queda suave con un poco de leche.

In that version, the sentence first gives the subject and result, and then adds the detail about what helps produce that result.