Learn Hardcore Portuguese (Brazil): Eu quero fazer um bolo delicioso.

Eu quero fazer um bolo delicioso. = I want to make a delicious cake.
Quero fazer um bolo delicioso. = Same meaning; a bit more natural in conversation.

You usually keep Eu if you want to emphasize I (as opposed to someone else), e.g. Eu quero fazer, não você.

Why is quero used instead of the infinitive querer?

Quero is the verb querer conjugated for the first person singular (I) in the present tense:

eu quero = I want
tu queres (rare in Brazil)
você quer = you want
ele/ela quer = he/she wants
nós queremos = we want
vocês/eles/elas querem = you all / they want

To say I want, you must conjugate the verb, so you use quero, not querer.

Is quero polite enough, or should I say something else to be more polite?

Quero is neutral and perfectly fine among friends, family, or in casual situations.

To sound more polite or softer (in a restaurant, with strangers, in formal contexts), Brazilians often use:

Eu gostaria de fazer... = I would like to make…
Eu queria fazer... = I wanted / I would like to make… (very common, sounds softer than quero)

So:

Eu quero fazer um bolo delicioso. – direct, neutral
Eu queria fazer um bolo delicioso. – more tentative, polite
Eu gostaria de fazer um bolo delicioso. – very polite, somewhat formal sounding

Why is it quero fazer and not quero de fazer or quero para fazer?

In Portuguese, some verbs are followed directly by another verb in the infinitive without a preposition. Querer is one of those verbs:

Quero fazer = I want to make
Quero comer = I want to eat
Quero estudar = I want to study

If you say quero de fazer or quero para fazer, it sounds incorrect or very unnatural in this context. The correct pattern is simply:

Querer + infinitive

So: Eu quero fazer um bolo delicioso.

Does fazer mean both to make and to do, like in this sentence?

Yes. Fazer can mean both to make and to do, depending on context.

Examples:

fazer um bolo = to make a cake
fazer a lição de casa = to do homework
fazer exercício = to do exercise

In Eu quero fazer um bolo delicioso, fazer is naturally understood as to make (to prepare/cook a cake).

Why is it um bolo and not uma bolo?

Because bolo is a masculine noun in Portuguese, so it takes the masculine article um.

um bolo (masculine) = a cake
uma casa (feminine) = a house

Grammatical gender in Portuguese does not always follow any logical rule; you just learn noun + article together:

o bolo, um bolo (masculine)
a torta, uma torta (feminine)

So um bolo delicioso is masculine throughout: um (m), bolo (m), delicioso (m).

What is the difference between um bolo and just bolo (without um) here?

Both are possible, but the nuance changes slightly.

Quero fazer um bolo delicioso.
- Emphasizes one (whole) cake, a specific unit: I want to make a (delicious) cake.
Quero fazer bolo.
- More general: I want to make cake (as a type of food), not focusing on a single unit.

In everyday speech, quero fazer um bolo is more common when you have in mind baking a cake as an event or project.

Why is the adjective after the noun: bolo delicioso and not delicioso bolo?

In Portuguese, the normal position for most adjectives is after the noun:

um bolo delicioso = a delicious cake
uma casa grande = a big house
um carro novo = a new car

You can put some adjectives before the noun (e.g. um delicioso bolo), but that usually sounds more poetic, emphatic, or stylistic. It can also slightly change the nuance of meaning in some cases.

For an everyday, neutral sentence, um bolo delicioso is the default and most natural order.

How does delicioso agree in gender and number?

Adjectives in Portuguese must agree with the noun in gender (masculine/feminine) and number (singular/plural).

For delicioso:

Masculine singular: delicioso – um bolo delicioso
Feminine singular: deliciosa – uma torta deliciosa
Masculine plural: deliciosos – uns bolos deliciosos
Feminine plural: deliciosas – umas tortas deliciosas

In the sentence um bolo delicioso, all are masculine singular: um (m.sg), bolo (m.sg), delicioso (m.sg).

Is delicioso a common way to say delicious, or do Brazilians prefer another word?

Delicioso is correct and widely understood, but in casual speech Brazilians often use:

muito gostoso = very tasty / really good
uma delícia = (it’s) delicious

So you might hear:

Quero fazer um bolo muito gostoso.
Quero fazer um bolo que seja uma delícia.

Your original sentence with delicioso is perfectly good, just a bit more textbook-style.

How do you pronounce Eu quero fazer um bolo delicioso in Brazilian Portuguese?

Approximate guide (using English-like sounds):

Eu – like “eh-oo” blended, often closer to “ehw”
quero – que like “keh”, ro like “roh” with a soft flap r (similar to American tt in “better”): “KEH-roh”
fazer – “fah-ZEHR”; the z sound in the middle, final -er often like “eh” or “ehr” depending on region
um – nasal, like “oong” but shorter
bolo – “BOH-loo”, stress on BO
delicioso – “deh-lee-see-OH-zoh”, stress on O (-o-zo)

Spoken smoothly, it sounds like:

ehw KEH-roh fah-ZEHR oong BOH-loo deh-lee-see-OH-zoh

Can Eu quero fazer um bolo delicioso also mean I am going to make a delicious cake (like a future plan)?

Yes, context can make quero sound like a plan or intention, similar to English I want to when used for plans:

Amanhã é aniversário dela. Eu quero fazer um bolo delicioso.
= Tomorrow is her birthday. I want to make / I’m planning to make a delicious cake.

If you want to focus more clearly on the future action, you could use:

Eu vou fazer um bolo delicioso. = I’m going to make a delicious cake.

But Eu quero fazer… often implies a future intention in real-life conversations.

Is this sentence formal, informal, or neutral in Brazilian Portuguese?

Eu quero fazer um bolo delicioso. is neutral.

Suitable for speaking with friends, family, and in most everyday situations.
For very formal contexts (e.g. talking to a client, in a formal email), you might soften it, e.g. Eu gostaria de fazer um bolo delicioso or Eu pretendia fazer um bolo delicioso depending on context.

In normal day‑to‑day Brazilian Portuguese, your original sentence is completely natural.