watasi ha tomato to tiizu wo tukatte, asagohan ni kantanna ryouri wo tukurimasita.

は marks 私 as the topic: as for me...

So 私は sets up the sentence from the speaker’s point of view. In a neutral sentence like this, は is very common.

If you used が instead, it would sound more like you are specifically identifying I as the person who did it, often with a sense of contrast or emphasis depending on context.

• 私は ... 作りました = As for me, I made ...
• 私が ... 作りました = I am the one who made ...

In everyday conversation, 私は is the more expected choice here.

Because トマト と チーズ forms one combined noun phrase: tomatoes and cheese.

Then を marks that whole phrase as the object of 使って.

So the structure is:

• トマトとチーズを使って = using tomatoes and cheese

You do not need:

• トマトをとチーズを ❌

That would be unnatural here. In Japanese, when several nouns are linked by と, the particle usually comes after the whole list.

Here, と means and when joining nouns.

So:

• トマトとチーズ = tomatoes and cheese

This is the normal way to make a complete, definite list of nouns in Japanese.

A useful comparison:

• A と B = A and B
• A や B = A and B, among other things

So と sounds more like a straightforward list of exactly those ingredients.

使って is the て-form of 使う (to use).

In this sentence, it connects 使う to the main verb 作りました. It shows that the first action is related to the second one:

• トマトとチーズを使って、料理を作りました
• I used tomatoes and cheese and made a dish
• more naturally: I made a simple dish using tomatoes and cheese

The て-form often links actions like this and can express:

• sequence: do A, then do B
• method/means: do B by using A

Here it mainly gives the idea of using tomatoes and cheese to make the dish.

The comma is mainly there to make the sentence easier to read.

Japanese commas often show a pause, especially after a long phrase like:

• トマトとチーズを使って、

It separates the using tomatoes and cheese part from the rest of the sentence.

The comma is helpful, but it is not always strictly required. You may also see the sentence written without it.

Here, に means something like for or at/as in relation to an occasion.

• 朝ご飯に = for breakfast

So the sentence says the dish was made for breakfast.

This に can mark a purpose, target, or time-related setting depending on the noun before it. Here it is very natural with meals:

• 朝ご飯にパンを食べます = I eat bread for breakfast
• 昼ご飯にうどんを作りました = I made udon for lunch

So 朝ご飯に does not mean the breakfast itself is the object; it means the dish is intended for that meal.

Because 簡単 is a な-adjective, not an い-adjective.

When a な-adjective directly modifies a noun, it takes な:

• 簡単な料理 = a simple dish

Compare:

• 静か → 静かな部屋
• 便利 → 便利なアプリ
• 簡単 → 簡単な料理

Even though 簡単 ends in a sound other than -i, the important point is its grammar class: it is a な-adjective.

Because Japanese is usually a verb-final language.

The basic order is often:

• topic / time / place / object / verb

So in this sentence, everything comes before the main action:

• 私は
• トマトとチーズを使って、
• 朝ご飯に
• 簡単な料理を
• 作りました

This is one of the biggest differences from English. In English, the verb comes earlier:

• I made a simple dish for breakfast using tomatoes and cheese.

In Japanese, the listener often has to wait until the end for the main verb.

Because the sentence is describing a completed action:

• 作りました = made

The dictionary form is 作る (to make).
The polite non-past form is 作ります (make / will make).
The polite past form is 作りました (made).

So the speaker is talking about something they already did.

It could definitely be omitted if the subject is already clear from context.

Japanese often leaves out subjects when they are obvious. So a very natural version would be:

• トマトとチーズを使って、朝ご飯に簡単な料理を作りました。

That can still mean I made a simple dish for breakfast using tomatoes and cheese, depending on context.

Including 私 is not wrong. It just makes the subject explicit, which is common in learner examples and sometimes used for clarity or contrast.

It can mean either cooking or a dish / food preparation, depending on context.

In this sentence, because it is something that was made, 簡単な料理 is best understood as:

• a simple dish
• a simple meal
• some simple food

So here 料理 refers to the thing prepared, not the general activity of cooking.

Not exactly.

• 朝ご飯を作りました = I made breakfast
• 朝ご飯に簡単な料理を作りました = I made a simple dish for breakfast

The actual sentence focuses on a simple dish and says it was made for breakfast. So the nuance is a little narrower than simply I made breakfast.

Because Japanese usually does not mark plural the way English does.

Whether トマト means tomato or tomatoes, and whether 料理 means a dish or dishes, depends on context.

Here, English naturally translates トマト as tomatoes because ingredients are often understood that way, but Japanese does not need a separate plural ending.

This is very normal:

• りんごを食べました = I ate an apple / apples
• 本を買いました = I bought a book / books

Context tells you which is most natural.