For salsa verde:
1 1/2 pounds tomatillos, peeled and cut in half
6 cloves garlic
1 small onion, roughly chopped
1 serrano or jalapeño pepper, stemmed and halved
juice of 1 lime
1/4 cup roughly chopped cilantro
1 tablespoon vegetable oil
1 ear corn, kernels removed
8 oz tortilla chips (we used multigrain, but the recipe originally called for corn tortilla chips)
1 cup canned black beans (about half of a 14-ounce can), drained and rinsed
1 avocado, thinly sliced
1 small onion, thinly sliced, slices placed in a bowl of cold water for 10 minutes
2 tablespoons chopped cilantro
1/2 cup toasted pumpkin seeds (pepitas)
crumbled cotija cheese
Preheat broiler to high. Place tomatillos, garlic, onion, and pepper on a foil-lined heavy-duty rimmed baking sheet. Broil without moving until well charred on top side, about 15 minutes. Flip vegetables with a spatula and continue broiling until well-charred and completely softened, about 15 minutes longer (ours didn't take nearly this long to char and soften, but then again, maybe we under-charred).
Transfer vegetables to a food processor and allow to cool for a few minutes. Add cilantro and lime juice. Process until roughly pureed. Season salsa verde to taste with kosher salt and set aside.
Heat oil in a medium skillet over high heat until smoking. Add corn kernels, toss to coat, and cook without moving until charred on one side. Toss and continue to cook, tossing occasionally until well charred all over, about 6 minutes total. Add black beans. Season to taste with kosher salt and remove from heat.
Heat 1 1/2 cups salsa verde and 1 cup water in a large saucepan until simmering. Add tortilla chips and fold with a rubber spatula until all the chips are coated. Transfer chips to a large serving dish or individual serving plates. Top with charred corn, black beans, avocado slices, sliced onion, chopped cilantro, toasted pumpkin seeds and cotija cheese.
Serve immediately with additional salsa verde.