Prep the oven and dish: Preheat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish with avocado oil or butter.

Prepare the chiles: If using canned green chiles, drain well and pat dry. If using poblanos, roast over an open flame or under the broiler until charred, steam in a covered bowl for 10 minutes, peel, seed, and slice into strips. Removing moisture helps the casserole set.

Sauté aromatics (optional but recommended): In a small skillet, sauté the diced onion in a teaspoon of oil over medium heat until soft, 3–4 minutes. Add garlic and cook 30 seconds. Let cool slightly.

Whisk the egg mixture: In a large bowl, whisk eggs, heavy cream, softened cream cheese, cumin, smoked paprika, salt, and pepper. Blend until mostly smooth; a few cream cheese bits are fine. Stir in the sautéed onion and garlic if using.

Layer the chiles and cheese: Spread half the chiles on the bottom of the dish. Sprinkle with half the shredded cheese. Add the remaining chiles and top with the rest of the cheese.

Pour and settle: Pour the egg mixture evenly over the layered chiles and cheese. Tap the dish gently on the counter to remove air pockets.

Bake: Place the dish on the middle rack and bake for 30–40 minutes, until the center is just set and the top is golden. A knife inserted near the center should come out mostly clean.

Rest and slice: Let the casserole rest for 10 minutes before slicing. This helps it firm up for cleaner portions.

Garnish and serve: Top with chopped cilantro. Serve with sour cream, avocado slices, or a drizzle of hot sauce.