Preheat oven's broiler, line a baking sheet with foil, and broil chiles for 5-10 minutes until blistered. Flip and broil for another 5-10 minutes.

Transfer chiles to a ziplock bag and steam for 10-15 minutes.

Peel skins off charred chiles, cut a slit and remove seeds.

Stuff chiles with Oaxaca cheese and seal with toothpicks.

Beat egg whites until stiff peaks, then gently fold yolks in to create batter.

Mix flour, salt, and garlic powder in a shallow dish for dredging.

Heat vegetable oil in a deep pan to 350°F (175°C).

Dredge stuffed chiles in flour mix and dip in egg batter, then fry until golden on both sides, about 2-3 minutes each.

Drain fried chiles on paper towels.

Blend tomatoes, onion, garlic, cilantro and salt until smooth for sauce.

Heat sauce in a medium saucepan until boiling, then simmer to blend flavors.

Serve hot chiles with warm sauce poured over them.