Мы решили запекать овощи на противне, потому что так нужно меньше масла.

Both are possible, but they mean slightly different things.

• запекать is the imperfective verb.
• запечь is the perfective verb.

In this sentence, Мы решили запекать овощи... sounds like we decided to roast/bake vegetables this way or we decided on the method of roasting vegetables. It focuses more on the activity or process.

If you said Мы решили запечь овощи..., it would sound more like we decided to roast the vegetables in one specific completed instance.

So the imperfective here fits the idea of choosing a cooking method, especially because the second half explains the reason: because that way less oil is needed.

Овощи is in the accusative plural.

Here it is the direct object of запекать:

• запекать что? — овощи

For plural inanimate nouns in Russian, the accusative usually looks the same as the nominative:

• nominative: овощи
• accusative: овощи

So although the form looks like nominative, its function here is accusative because it is the thing being roasted.

На противне means on a baking tray / on a sheet pan.

The noun противень is in the prepositional case singular after на when на means location.

• противень = baking tray
• на противне = on the baking tray

This follows a common pattern:

• на столе = on the table
• на полу = on the floor
• на противне = on the baking tray

So here на means on, and because it describes where the vegetables are roasted, Russian uses the prepositional case.

Противень is a masculine noun with a soft sign (-ь) at the end. In the prepositional singular, many nouns like this take -е:

• день → о дне
• словарь → в словаре
• противень → на противне

So the stem changes from противень to противне in that case form.

This is just the normal prepositional singular form of the noun.

Here так means something like this way, like this, or in this manner.

In the sentence:

• потому что так нужно меньше масла

the word так refers back to the method just mentioned: roasting the vegetables on a baking tray.

So the idea is:

• because this way less oil is needed
• because when you do it like this, you need less oil

It does not mean simply so in the sense of therefore here. It specifically points to the method.

This is a very common Russian structure. Russian often uses impersonal sentences where English would use you need, we need, or it takes.

• нужно меньше масла literally means something like less oil is necessary
• in natural English: you need less oil or it takes less oil

There is no explicit subject because Russian does not always need one in this kind of statement. The focus is on the general fact, not on who exactly needs the oil.

So так нужно меньше масла is a very natural way to say this way, less oil is needed.

Because меньше normally takes the genitive in Russian.

• меньше чего? — масла

This is similar to how Russian handles quantities and comparison words:

• много воды = a lot of water
• мало времени = little time
• больше денег = more money
• меньше масла = less oil

So масла is genitive singular of масло.

Мы решили is the past tense plural form of решить.

• решить = to decide
• мы решили = we decided

Russian past tense agrees with the subject in gender/number, not person:

• я решил = I decided (masculine speaker)
• я решила = I decided (feminine speaker)
• мы решили = we decided

So the ending -и shows plural, matching мы.

Because потому что introduces a subordinate clause meaning because.

The sentence has two parts:

• Мы решили запекать овощи на противне
• потому что так нужно меньше масла

In Russian, clauses introduced by потому что are normally separated by a comma.

So the comma is required here.

Yes, but it would mean something slightly different.

• в духовке = in the oven
• на противне = on a baking tray

These are not exact substitutes:

• в духовке tells you the general place where the cooking happens.
• на противне tells you the surface/container the vegetables are on.

You could even combine them:

• Мы решили запекать овощи на противне в духовке.

That would mean We decided to roast the vegetables on a baking tray in the oven.

Yes, that is grammatically correct, but the nuance changes.

• решили запекать = decided to roast vegetables / decided on roasting as the method
• решили запечь = decided to roast the vegetables in this particular instance

So if you are talking about a general cooking choice or method, запекать works well.

If you are talking about one concrete action with a clear result, запечь is often more natural.

Both are possible depending on what exactly you want to emphasize.

It can correspond to both in English.

Russian нужно in this structure is very flexible. Depending on context, it can be translated as:

• less oil is needed
• you need less oil
• it takes less oil

The Russian sentence is slightly more impersonal and general than everyday English you need less oil.

So if you are translating naturally, any of those can work, depending on style.

The usual stress is:

• проти́вень
• на проти́вне

The stress stays on ти́.

That is useful to remember because the spelling changes in the case form, but the stress does not move here.