How to Make It
In a large, enameled cast-iron casserole, heat the olive oil. Add the onions and a generous pinch of salt and cook over moderate heat, stirring occasionally, until softened and just starting to brown, about 8 minutes. Add the garlic, cardamom, pepper and ajwain and cook, stirring occasionally, until nicely browned and the pot is slightly dry, about 8 minutes.
Add the collards to the casserole in large handfuls, letting each batch wilt slightly before adding more. Cover and cook over moderate heat, stirring occasionally, until the collards are just tender, 15 to 20 minutes. Uncover the casserole and cook, stirring, until the most of the liquid has evaporated, about 5 minutes. Season with salt and serve.