‘𝐎𝐛𝐞𝐫𝐰𝐢𝐥 𝐛𝐞𝐢 𝐁𝐮̈𝐫𝐞𝐧’, a dual-purpose perennial leek from the Pearl-onion group:

This very rare cultivar of Swiss origin was historically grown for both its bulbs and pseudostems in Oberwil bei Büren, in the canton of Bern.
It is conserved by ProSpecieRara and, since Switzerland is outside the European Union, has so far not been distributed within the EU! 

It appears to me to belong to the same lineage as ‘Oerprei’, with which it shares many characteristics.
However, it differs in its reluctance to flower in cool climates and, consequently, in its ability to form unsegmented bulbs, round like onions.
When the bulbs do divide, they are composed of cloves arranged in a fan-like pattern.

The bulbs and cloves have a mild flavor and can be pickled or eaten cooked. They work well in a wide variety of recipes and develop a meltingly tender texture when cooked.
The pseudostems reach around 3 cm in diameter and 20 cm in length, with a mild flavor and a texture that holds up well during cooking.

The plants are unaffected by disease, highly cold-hardy (down to −20 °C and perhaps even lower), and also perform very well under drought conditions.

Another perennial leek as indestructible as it is useful, which I am now making available internationally!