Preheat your oven to 400°F (200°C). Wash the poblano peppers and cut them in half lengthwise. Remove the seeds and membranes.
Place the pepper halves on a baking sheet lined with parchment paper. Drizzle with olive oil and sprinkle with sea salt. Roast for about 15 minutes until softened and blistered.
In a large skillet over medium heat, add olive oil. Sauté the diced red onion for about 3 minutes until translucent. Add cauliflower, red bell pepper, cumin, coriander, oregano, and garlic. Sauté for 5-7 minutes until tender.
In a mixing bowl, combine sautéed vegetables with black beans, rice, spinach, lime juice, and tomatillo salsa. Season with salt and pepper. Mix well.
Stuff each pepper half with the filling mixture. Sprinkle cheese on top if desired.
Return stuffed peppers to the oven and bake for an additional 15-20 minutes until tender and cheese is melted.
Let cool slightly before serving, garnished with avocado, tomatillo salsa, and a dollop of green chile cashew cream or crumbled cheese.