Em casa, misturei farinha, fermento, canela e baunilha para fazer um bolo.

Em casa means at home.

Portuguese often puts a place expression at the beginning of the sentence to set the scene. So Em casa, misturei... is like saying:

• At home, I mixed...
• or more naturally in English, I mixed ... at home.

Both word orders are possible in Portuguese:

• Em casa, misturei farinha...
• Misturei farinha... em casa.

Starting with Em casa gives a little more emphasis to the location.

This is a very common question.

Em casa is a fixed, very common expression meaning at home in a general sense.

• Estou em casa. = I’m at home.
• Fiquei em casa. = I stayed at home.

Na casa usually means in the house / at the house of a specific person or place, not just home in general.

For example:

• Estou na casa da minha avó. = I’m at my grandmother’s house.
• Vou na casa do João. = in European Portuguese, this would more naturally be Vou a casa do João or Vou para casa do João, depending on meaning.

So in your sentence, em casa is the normal way to say at home.

Because Portuguese often drops the subject pronoun when the verb ending already shows who is doing the action.

Misturei means I mixed. The ending -ei tells you the subject is eu.

So:

• Misturei farinha... = I mixed flour...
• Eu misturei farinha... = also correct, but more emphatic

Portuguese usually leaves out eu unless it is needed for:

• emphasis
• contrast
• clarity

For example:

• Eu misturei os ingredientes, mas ele fez o resto.
  = I mixed the ingredients, but he did the rest.

Misturei is the pretérito perfeito in European Portuguese.

It is used for a completed action in the past. Here it means the mixing happened and is finished.

So:

• misturo = I mix / I am mixing (present, depending on context)
• misturei = I mixed
• misturava = I used to mix / I was mixing
• tenho misturado = I have mixed / I’ve been mixing, depending on context

In this sentence, misturei is the natural choice because it describes one completed action.

It comes from the verb misturar = to mix.

This is a regular -ar verb. In the eu form of the pretérito perfeito, -ar verbs usually end in -ei:

• falar → falei = I spoke
• comprar → comprei = I bought
• misturar → misturei = I mixed

Notice the spelling:

• misturar
• misturei

The u is kept so that the g sound of the stem does not change. This is just part of standard Portuguese spelling.

Portuguese often omits articles when talking about ingredients or substances in a general way, especially in recipe-like contexts.

So this sounds natural:

• misturei farinha, fermento, canela e baunilha

This is similar to English saying:

• I mixed flour, baking powder, cinnamon and vanilla

If you add articles, the meaning can become more specific:

• misturei a farinha = I mixed the flour
• misturei o fermento = I mixed the baking powder/yeast

That would usually refer to specific ingredients already identified in the context.

So in your sentence, no articles sounds very natural because it is just naming ingredients.

In cooking, fermento can refer to a leavening agent.

Depending on the context, it may mean:

• yeast
• baking powder
• sometimes more generally something that helps dough or batter rise

In a sentence about making um bolo (a cake), many learners will understand fermento here as baking powder, though the exact meaning can depend on the full recipe.

In Portugal, you may also see more specific expressions such as:

• fermento em pó = baking powder
• fermento de padeiro = baker’s yeast

So fermento on its own is slightly broad, but in a cake context it is easy to understand.

The comma separates the opening location phrase from the main clause:

• Em casa, misturei...

This is very common when a sentence begins with an adverbial phrase such as place, time, or manner:

• Ontem, fui ao mercado.
• Na cozinha, preparei o jantar.
• Com cuidado, abriu a caixa.

The comma is helpful and natural here, especially in written Portuguese. Without it, the sentence would still usually be understandable, but the comma makes the structure clearer.

Para here expresses purpose: it tells you why the ingredients were mixed.

So:

• misturei ... para fazer um bolo
• I mixed ... to make a cake

This structure is very common in Portuguese:

• Estudo para aprender. = I study to learn.
• Fui ao supermercado para comprar leite. = I went to the supermarket to buy milk.

After para, Portuguese often uses the infinitive when the subject is the same as in the main verb.

Here, the same person who mixed the ingredients is also the one making the cake, so fazer is the natural form.

Because after para in this kind of purpose clause, Portuguese normally uses the infinitive.

So:

• para fazer = to make
• not para faço
• not para fiz

This is similar to English:

• I mixed the ingredients to make a cake.

You use the infinitive because it expresses purpose, not a separate main action with its own tense.

If you wanted a different structure with an explicit subject, Portuguese could use something like:

• para eu fazer um bolo = for me to make a cake

But in your sentence, that is unnecessary because the subject is already understood.

Because bolo is a masculine noun in Portuguese.

So the correct indefinite article is:

• um bolo = a cake

Compare:

• um bolo = a cake
• o bolo = the cake

If the noun were feminine, you would use uma:

• uma receita = a recipe
• uma cozinha = a kitchen

Grammatical gender in Portuguese does not always match natural gender; it is simply a property of the noun that you have to learn.

Yes, absolutely.

Fazer um bolo is the standard, natural way to say to make a cake.

Portuguese can also use verbs related to baking, but fazer is the broad, everyday choice:

• Vou fazer um bolo. = I’m going to make a cake.
• Ela fez um bolo de chocolate. = She made a chocolate cake.

If you wanted to focus specifically on the oven step, you might see other verbs in other contexts, but fazer um bolo is perfectly normal and probably the most useful expression to learn.

In Portuguese, as in English, you normally do not put a comma before e when it simply joins the last item in a list.

So this is standard:

• farinha, fermento, canela e baunilha

That matches the usual pattern:

• item 1, item 2, item 3 e item 4

A comma before e is only used in special cases, not in an ordinary simple list.

Yes. Portuguese is flexible with word order, especially with phrases like Em casa.

Some natural alternatives are:

• Misturei farinha, fermento, canela e baunilha em casa para fazer um bolo.
• Para fazer um bolo, misturei farinha, fermento, canela e baunilha em casa.
• Em casa, para fazer um bolo, misturei farinha, fermento, canela e baunilha.

All are grammatical, but they place emphasis differently:

• Em casa first emphasizes location
• Para fazer um bolo first emphasizes purpose
• the original sentence is very natural and balanced

It can work as both, but it sounds especially natural as an everyday sentence describing a cooking action in the past.

For example:

• Ontem, em casa, misturei farinha, fermento, canela e baunilha para fazer um bolo.

In an actual recipe, Portuguese often uses:

• the imperative: Misture a farinha, o fermento...
• or a more impersonal style

Your sentence sounds like someone narrating what they did, not giving instructions. So it is excellent for learning past tense narrative Portuguese.