Not sure how you'd figure the complicated part. Number of ingredients?
Number of steps? Length of time in the kitchen?

I find it hard to pin on any one thing. I made pot stickers once. The
recipe made a ton and it took me many hours to do it. Same for ravioli when
I made a lot. Made puff pastry from scratch. That wasn't worth it. Have
also made Chinese Tomato Beef. Although it wasn't hard, it was a lot of
prep work. You have to partially freeze the beef to slice it and there are
so many different vegetables that need to be stir fried for different
lengths of time. Then there is the sauce. Baklava is time consuming. So
are hominy croquettes.

I think probably the one thing that gave me the most difficulty aside from
pie crust is taffy. I have tried assorted recipes and I somehow always
manage to cook it for too long. Turns into a potential tooth breaker.