That might be obvious but they taste like matcha, just sweet. Too sweet.
I love to drink matcha but the drink is just the right kind of bitter and every dessert I've ever tried is way too sweet. I really don't like it but some people can't get enough of them. It's really one of the things you need to try for yourself.

And no Dunkin' Donuts in Japan so I can't compare.

Akili Li wrote:How do the specials work? Are they daily or different every week, or does each shop have a special they're known for that doesn't change at all?


(Sorry, sometimes my brain is a weird place to live)

Depends on the shops. Most places at least have a special menu each season, like for example Mister Donuts had cherry blossoms donuts when they bloomed and now, rather than donuts, they have shaved ice as a time limited treat.
On the other hand, Starbucks releases a new drink every two weeks lately.

I've gotten a delta biscoff on my one and only delta flight so I'm pretty sure you can find the same exact brand in the US.

That being said, speculoos + coffee is one of my favorite combo ever.
And using speculoos as a base for cheesecake is another one of my guilty pleasure.

I don't think I've ever had biscoff. I've heard of it before.
I like to dunk my oreos in my coffee. That's delicious.