Here's an interesting exotic vegetable for you and it's called calcots. Now It's pretty much similar to green onions but in a different way of cultivating.

1. EXOTIC
CALCOTS
The humble Calcots came into
existence, when a Spanish farmer
cultivated conventional green onions in a slightly unconventional
manner. This event supposedly happened somewhere at the junction of
the nineteenth and twentieth century. This little vegetable has now
gained rapid popularity all over the world and is a subject of
major culinary interest. In fact, it has become an integral part of the
culture of its native country.
Some mouth watering facts about Calcots:
Method of cultivation: Farmers begin with them just like they begin with
the ordinary scallions; they dig trenches in the ground and bury the bulbs
inside. But this is very the similarity comes to an end.
The stalks are covered with soil, but some part of it is left exposed. As the
plant grows and develops, more soil is added, but some part is always
allowed to remain above ground. In fact, these scallions get their name
from their method of cultivation.
After some time, the plants are carefully uprooted in stored for a few
months. During this period, they remain untouched and undisturbed.
Then, when the winter season arrives, they are taken out of storage and
buried inside the ground once again.

2. This time, they are buried completely and left like that until they are fully
matured. After this, they are harvested normally.
This entire process takes nearly a year to completely, because it spans
nearly two seasons. Also, it takes a lot of skill to cultivate them. The
farmer should know exactly how much portion of the plant has to be left
exposed, how frequently and when he is supposed to add soil. He should
uproot them at the right time, store them properly and then replant and
harvest them in the correct manner. This is truly an art.
Method of cooking and consumption: Conventional onions are generally
eaten as part of salad, or they are used in soups and other dishes. These
little variants, on the other hand, are consumed by themselves, as
separate entities altogether.
These are carefully grilled on barbecue units. They are gently cooked to
just the right temperature which will char the outermost layer and bring
out the flavours of the inner core. At the end of this period, the stalks are
gently wrapped in papers and allowed to stay put for fifteen to twenty
minutes. Then, they are removed from the wrapping. The blackened coat
is peeled off. The delicious core is enjoyed along with sauces and red
wine.
Cooking these is as complicated as cultivating them. You can easily burn
them if you are not careful. Too little heat will bring out the taste that
you are looking for. The inner core should be cooked to achieve a tender,
soft cheese-like consistency.
Calcots are so popular that there is an entire food festival dedicated to
them. In this only these onions are consumed in bulk, and no other dishes
are served. This is held biannually and is very popular internationally.