Мы заказали чай, а вдобавок взяли чизкейк.

we

Breakdown of Мы заказали чай, а вдобавок взяли чизкейк.

• чай: the tea
• взять: to take
• а: and

Questions & Answers about Мы заказали чай, а вдобавок взяли чизкейк.

What does вдобавок mean here?

Вдобавок means in addition, on top of that, or besides.

In this sentence, it adds the idea that after ordering tea, they also got cheesecake as an extra thing:

• Мы заказали чай, а вдобавок взяли чизкейк.
• We ordered tea, and in addition we got cheesecake.

It is an adverb, so it does not change form here.

You may also see similar words and expressions such as:

• к тому же = besides / moreover
• кроме того = in addition / furthermore
• ещё = also / more

Вдобавок often has a slightly natural, conversational feeling of as an extra or on top of that.

Why is а used instead of и?

In Russian, а does not always mean a strong but. It can also connect two related ideas while lightly contrasting or separating them.

Here:

• Мы заказали чай, а вдобавок взяли чизкейк.

The speaker is presenting two actions:

1. they ordered tea
2. they also got cheesecake

Using а makes the second part feel like an added, slightly separate step: and additionally / and on top of that.

If you used и, the sentence would also be possible in many contexts:

• Мы заказали чай и вдобавок взяли чизкейк.

That sounds a bit more like simple addition.
With а, the sentence has a natural spoken flow: we ordered tea, and then besides that, we got cheesecake too.

So here а is not a strict but; it is more like a linking word with a mild contrast or shift.