Preheat your broiler to high. Place the Hatch chiles on a baking sheet and roast them under the broiler for 10 to 20 minutes, turning occasionally, until the skins are blistered.

Transfer the hot roasted chiles into a ziplock bag and seal it tightly. Allow them to steam for 10 to 15 minutes to loosen the skins.

After peeling, slice open each chile lengthwise and remove the seeds. Stuff each chile with Oaxaca cheese, about 1 ounce per pepper, and secure openings with toothpicks.

In a mixing bowl, separate egg whites from yolks. Whip egg whites until stiff peaks form, then gently fold in the yolks.

Combine all-purpose flour with salt and garlic powder in a shallow dish. Lightly coat each stuffed chile in the flour mixture, then dip into the egg batter.

Heat vegetable oil in a deep skillet over medium heat. Carefully add coated chiles in batches, frying for about 2 to 3 minutes per side until golden brown.

Blend tomatoes, onion, garlic, cilantro, and salt in a blender until smooth. Pour into a saucepan and bring to a boil, then simmer for about 10 minutes.

Serve the hot stuffed chiles on a plate and spoon warm tomato sauce over them. Optionally add sliced jalapenos or cilantro.