1. Roast the Peppers:

• Preheat your oven or grill to 400°F (200°C).
• Place the poblano peppers (or any large peppers you’re using) on a baking sheet and roast them in the oven for about 10-15 minutes, turning them occasionally with tongs until the skins are charred and blistered.
• Alternatively, you can roast them directly on the stove top over an open flame using tongs, or on a grill.
• Once the peppers are charred, remove them from the oven or grill and place them in a plastic bag or covered bowl to steam for about 10 minutes. This helps loosen the skin and makes peeling easier.
• After the peppers have cooled slightly, peel off the charred skins and make a slit down the side of each pepper to remove the seeds and membranes, taking care not to tear the peppers. Set aside.

2. Prepare the Stuffing:

• In a pan, heat the vegetable oil over medium heat. Add the chopped onion and garlic, cooking until softened, about 3-4 minutes.
• Add the ground meat (beef, chicken, turkey, or black beans for a vegetarian option), and cook until browned and fully cooked through. Season with ground cumin, oregano, salt, and pepper. Remove from heat and let the filling cool for a few minutes.
• Stir in the shredded cheese (reserve some cheese for topping if desired). Mix until the cheese is melted and the filling is well combined.

3. Stuff the Peppers:

• Carefully stuff each roasted pepper with the prepared filling, packing it gently. Don’t overstuff, as the peppers may tear. You can fold the opening of the pepper slightly to secure the stuffing inside.

4. Prepare the Batter:

• In a clean bowl, separate the egg whites from the yolks. Beat the egg whites with a pinch of salt until soft peaks form.
• In a separate bowl, whisk together the egg yolks, flour, baking powder, and milk until smooth.
• Gently fold the beaten egg whites into the yolk mixture. This will create a light, airy batter for coating the stuffed peppers.

5. Fry the Chiles Rellenos:

• Heat about 2 tablespoons of vegetable oil in a large skillet over medium-high heat.
• Dip each stuffed pepper into the batter, coating it evenly on all sides. Carefully lower the battered pepper into the hot oil.
• Fry the peppers for about 2-3 minutes per side, or until golden brown and crispy. Use tongs to carefully flip the peppers, ensuring they don’t tear.
• Once the peppers are fried, remove them from the skillet and place them on a paper towel-lined plate to drain any excess oil.

6. Make the Tomato Sauce:

• In a separate pan, heat 1 tablespoon of vegetable oil over medium heat. Add the chopped tomatoes, onion, and garlic, cooking for about 5 minutes until softened.
• Add the serrano or jalapeño peppers if using, and cook for another 2 minutes. Season the sauce with salt, pepper, and sugar to taste. Let the sauce simmer for another 5-7 minutes until it thickens slightly.
• Use a blender or immersion blender to purée the sauce until smooth, or leave it chunky for a more rustic texture.

7. Serve:

• Place the fried Chiles Rellenos on a serving platter, and spoon the freshly made tomato sauce over the top.
• Garnish with additional cheese, chopped cilantro, or sour cream if desired.
• Serve with a side of rice, refried beans, or Mexican crema for a complete meal.

Tips:

• Pepper Substitutes: If poblano peppers are not available, you can use other large, mild peppers like Anaheim, pasilla, or even bell peppers for stuffing.
• Make-Ahead: You can roast and stuff the peppers in advance, and then fry them just before serving. This can save you time when preparing the dish for a crowd.
• Vegetarian Option: For a meatless version, substitute the ground beef with black beans, corn, and extra cheese for a hearty and satisfying filling.
• Salsa Variations: Some variations of Chiles Rellenos are served with a green tomatillo salsa or sour cream-based sauce, so feel free to experiment with different toppings.