Toast the cumin seeds in a dry skillet over medium heat until fragrant, 2 to 3 minutes, stirring frequently. Let cool slightly, then grind with a spice grinder or mortar and pestle.
1 Tbsp plus 1 teaspoon whole cumin seed
Add the pork, tomatillos, poblano peppers, Anaheim peppers, jalapeños, bell pepper, green onions, onion, garlic, oregano, ground cumin, salt, and optional habanero peppers to the Instant Pot.Press Sauté and cook just until everything begins to sizzle, about 3 to 5 minutes. 4 pounds boneless pork shoulder, ¾ pound tomatillos, ⅔ pound Poblano peppers, 6 ounces Anaheim peppers, 2 jalapeno or serrano chilles, ½ yellow bell pepper, ½ cup chopped green onions, 1 medium white onion, 7-8 medium cloves garlic, 1 tsp dried Mexican oregano, 1 tsp Kosher salt, 1-2 habanero peppers
Lock the lid, set the valve to Sealing, and cook on High Pressure (Manual) for 28 minutes. Quick release the pressure.
Transfer the pork to a bowl with tongs or a slotted spoon.Add the cilantro and fish sauce to the vegetables in the pot. Blend until smooth with an immersion blender or carefully transfer to a countertop blender. Taste and season with additional salt if needed. ½ cup loosely packed fresh cilantro leaves and tender stems, ½ Tbsp Asian fish sauce
Return the pork to the sauce and stir gently to combine. Serve immediately, or for the best flavor, refrigerate overnight and reheat before serving.