Place poblano peppers on a sheet pan and broil under high heat. Turn them frequently and move tray around until they are charred on all sides. Remove and place in large bowl or pan and cover tightly so they can steam.While the peppers are steaming, peel the papery skins off the tomatillos, halve the serranos and simmer in a pot of water until they are softened (about 15 minutes).Optional: toast the pumpkin seeds in a dry skillet over medium heat until they start to pop, 3 to 4 minutes.
When the poblano peppers are cool enough to handle, pull out the stems and seeds, and remove the skins (some bits of skin may be left on peppers and that’s OK). Place the peppers in a blender container.
Drain the water from the saucepan and place the softened tomatillos and serranos in the blender with the poblanos. Add 2 cups of chicken stock, onion, garlic, cilantro, pumpkin seeds, and salt, and blend on high until everything is smooth.
2 cups chicken stock, 1 onion, 3 cloves garlic, 1/2 cup cilantro, 1 teaspoon salt
Heat oil in a large skillet over medium heat and sauté the chicken thighs 15 to 20 minutes, until the chicken reaches 165°F. Alternatively, grill the chicken thighs or cook in your favorite method.When chicken is cooked through, pour the Verde sauce into the skillet over the chicken pieces and bring the sauce to a simmer. Add more water or stock if the sauce seems too thick. Taste and add more salt if needed.Do not simmer the chicken and sauce for too long or the bright colors of the sauce will turn a drab olive green.