haha ha bangohan ni korokke wo tukurimasita.

は marks 母 as the topic of the sentence: As for mother, ...

In this sentence, the speaker is simply telling you what the mother did, so は is very natural.

• 母は晩ご飯にコロッケを作りました。
  As for mother, she made croquettes for dinner.

If you used が instead, it would sound more like you are specifically identifying mother as the person who did it, often in contrast to someone else or as new information.

• 母が晩ご飯にコロッケを作りました。
  Mother made croquettes for dinner.
  (possibly implying not someone else)

Here, 晩ご飯に means for dinner.

The particle に can mark a purpose or occasion in sentences like this. So:

• 晩ご飯にコロッケを作りました = made croquettes for dinner

It does not mean at dinner in the physical-location sense. It means the croquettes were made to be eaten as dinner / for the dinner meal.

This is similar to patterns like:

• お弁当にサンドイッチを作る = make sandwiches for a lunch box
• 朝ご飯に卵を焼く = fry eggs for breakfast

Usually, に is the better choice here.

• 晩ご飯にコロッケを作りました = made croquettes for dinner

If you use で, it would more naturally suggest at dinner or during dinner, which does not fit as well with making the food.

So in this sentence:

• に = for dinner, as the dinner item
• で = at/during dinner, which is less natural here

を marks the direct object of the verb.

The verb is 作りました (made), and the thing being made is コロッケ.

So:

• コロッケを作りました = made croquettes

This is very common in Japanese:

• ご飯を食べました = ate a meal / rice
• 本を読みました = read a book
• ケーキを作りました = made a cake

Japanese normally uses SOV word order: subject/topic + object + verb.

English is usually SVO:

• Mother made croquettes

Japanese is usually:

• Mother croquettes made
• 母はコロッケを作りました

In this sentence, there is also 晩ご飯に in the middle:

• 母は / 晩ご飯に / コロッケを / 作りました
• As for mother / for dinner / croquettes / made

The verb usually comes at the end in ordinary Japanese sentences.

作りました is the polite past form of 作る (to make).

Breakdown:

• dictionary form: 作る
• polite non-past: 作ります
• polite past: 作りました

So 作りました means made.

This form is commonly used in polite conversation and textbook Japanese.

This is an important Japanese usage point.

When speaking about your own mother to someone else, Japanese often uses 母（はは）.

• 母 = my mother / one’s own mother, in a relatively neutral or humble way
• お母さん = mom / mother, often used when talking to your mother or when referring to someone else’s mother more politely

So if the speaker is talking about their own mother, 母 is natural.

Examples:

• 母は先生です。 = My mother is a teacher.
• お母さん、見て！ = Mom, look!
• お母さんはお元気ですか。 = Is your mother well?

Japanese often leaves out information that is understood from context.

If the speaker says 母, it is usually already understood to mean my mother unless the context says otherwise. So 私の母 is possible, but often unnecessary.

• 母は晩ご飯にコロッケを作りました。
  = My mother made croquettes for dinner.

Using 私の母 can sound more explicit, and sometimes a little heavier than necessary in normal conversation.

Japanese nouns usually do not show singular/plural the way English nouns do.

So コロッケ can mean:

• a croquette
• croquettes

The exact number depends on context.

In this sentence, English would probably translate it as croquettes or croquettes for dinner, because making just one croquette for dinner would be less likely, but grammatically the Japanese itself does not force singular or plural.

In this sentence:

• 母 = はは
• 晩ご飯 = ばんごはん
• 作りました = つくりました

A full reading would be:

• はは は ばんごはん に コロッケ を つくりました。

One useful note: 母 is often read はは when referring to one’s own mother in a sentence like this.

They are very similar. Both can mean dinner / evening meal.

• 晩ご飯（ばんごはん）
• 夕ご飯（ゆうごはん）

In many situations, they are interchangeable. The choice often depends on habit, region, or personal preference.

So this sentence could also be said as:

• 母は夕ご飯にコロッケを作りました。

and the meaning would be basically the same.

Not natural English. The natural translation is Mother made croquettes for dinner.

The に after 晩ご飯 does not correspond neatly to a single English preposition in every case, so translating it word-for-word can sound strange. In this sentence, the best natural meaning is:

• Mother made croquettes for dinner.

This is a good example of why Japanese particles should be understood by their function in context, not always by a fixed one-word English equivalent.