Not just for collards. A mixture of greens is good, too.
8 c water
1 T salt, optional
2 bunches collards, or other greens, or a combination
2 T butter or oil
1 large onion, chopped
1 t ground ginger
1 t ground cumin
1/4 t ground cardamom
1/4 t ground cinnamon
1. Bring water to the boil. Wash and stem greens. Roll up the leaves and cut them crosswise into thin strips. This is called chiffonade. When the water is boiling, add salt, if using. Stir in collard strips and return to the boil. Boil gently until tender, or to your preference, about 15 minutes. Drain into a colander set over a bowl. Reserve the cooking liquid.
2. Place the same pot or a skillet over low heat. Melt butter or heat oil. Add the onion and cook until softened, about 5 minutes. Add the spices and cook for 1 or 2 minutes, until fragrant. Add the chopped collards and 1 cup of the reserved cooking liquid. Increase heat so that the mixture starts to simmer. Cover and simmer gently for about 10 minutes.
3. Uncover, raise heat and boil until liquid reduces to a saucy consistency. Serve hot.