Ethiopian Collard Greens

adapted from Saveur

4 T unsalted butter
1/8 t whole black cardamom seeds
1/8 t ground fenugreek
1/4 c extra-virgin olive oil
1 large yellow onion, minced
3 cloves garlic, minced
2 fresh Thai chiles, stemmed, seeded, and minced*
1, 1-inch piece ginger, peeled and minced
1 1/2 lbs. collard greens, stemmed and cut crosswise into ¼"-wide strips
Kosher salt and freshly ground black pepper, to taste
White wine vinegar, to taste

Heat butter in a 6-qt. pot over medium heat. Add cardamom, and cook, stirring often, until fragrant, 1–2 minutes. Increase heat to medium-high and add oil; add onions and cook, stirring often, until browned, 10 minutes. Add garlic, chiles, and ginger and cook, stirring often, until soft and fragrant, 3 minutes. Add collards, 1 1/2 cups water, and salt and pepper; cover and bring to a boil. Reduce heat to low and cook, stirring occasionally, until collards are tender, 50–55 minutes. Stir in vinegar and serve collards hot.

* Substitute dried cayenne to taste if unavailble or fresh milder chiles if desired.