1 pound tomatillos, remove husks and rinse
1 jalapeño
1/2 serrano, deveined, seeded
2 Tbsp olive oil
1 medium onion, diced (about 2 cups)
1 large garlic clove, minced
1/3 cup cilantro
2 cups chicken stock
10 baby red potatoes, scrubbed, cut into small pieces
1 15-ounce can small white beans, drained and rinsed
1 Tbsp fresh squeezed lime juice
2 cups rotisserie chicken, cut into small pieces
1 ear of corn, roasted, cut kernels from cob
Line a baking sheet with heavy duty foil. Place the tomatillos and peppers on one end. Place the small pieces of potato on the other end of the sheet.
Roast the potatoes, tomatillos and chiles on a baking sheet 4 inches below a very hot broiler until darkly roasted, even blackened in spots, about 5 minutes. Flip them over and roast the other side — 4 or 5 minutes more will give you splotchy-black and blistered tomatillos and chiles that are soft and cooked through. Cool and transfer everything but the potatoes to a food processor or blender, also pour any juices that have run out onto the baking sheet. Process until smoothly pureed. The potatoes may not be completely tender. They can finish cooking as the soup simmers after adding the chicken, beans and corn.
While the tomatillos, peppers and potatoes are in the boiler, prepare the remaining ingredients for the soup base.
Add the olive oil to a Dutch oven that has been heated over medium. When it is warm, add the onions. Saute until they are soft and transparent. Add the garlic and continue to cook for another 2 minutes.
Pour the tomatillo mixture into the Dutch oven. With an immersion blender puree the soup. Put the heat on medium-low to reheat the mixture. Add the chicken, potatoes, corn kernels and white beans. Simmer until the potatoes are tender. Add the lime juice. Season the soup with salt and pepper to taste.
Serve the soup with a dollop of sour cream, additional lime wedges and cilantro if desired.