Add the corn and boil until tender, about 10 minutes.

NPR: Recipe: 'Inspired by Ingredients'

Bring to a boil, then reduce the heat, and simmer for about 1 hour or until tender.

NPR: Recipes: 'Vefa's Kitchen'

Put them in a saucepan with lightly salted water to cover, bring to a boil over high heat, reduce the heat to low, and simmer until the leeks are very tender, about 20 minutes.

CNN: Keftes de Prasa (Leek Fritters)