Instructions
Heat olive oil in large pot or Dutch oven.
Add chopped onions, saute until translucent. Add garlic, cook for another minute or so until garlic is fragrant. Remove onion and garlic from pot.
Add tomatillos to pot and cover with water. Bring to a boil, reduce to a simmer, and cook until tomatillo skins start to split, about 10 minutes.
Drain water, and puree tomatillos in food processor or blender.
Add tomatillos back to pot, along with green chiles, chicken broth, salt, oregano, and cumin. Simmer for 10 minutes. Mix 2 tablespoons of cornstarch with 2 tablespoons of water and add to green chile and tomatillo mixture.
Continue simmering for about 5 more minutes, allowing sauce to thicken.
Add mixture back to food processor or blender, along with 1/4 cup cilantro, and lime juice. Add salt to taste.
Source: allrecipes.com
