neutral oil • medium yellow onion, finely diced • scallions, white parts only, thinly sliced • large garlic cloves, minced • tomatillos, husked and quartered • small Serrano or other mild green pepper, seeded and diced • cans chickpeas, drained and rinsed • water, vegetable stock, or chicken stock • Optional for serving: shredded pepper jack cheese, sour cream, sliced scallion greens, cilantro, rice, tortillas, tortilla chips