Preheat your broiler or light an open flame. Place the poblano peppers directly under the broiler or over the flame, turning occasionally, until the skins are charred and blistered, about 8–10 minutes.

Transfer the roasted peppers to a plastic bag or a covered dish, sealing it tightly and allow to steam for about 15 minutes.

Carefully peel the charred skins off the poblano peppers using your fingers or a paper towel.

Make a slit along one side of each pepper, gently removing the seeds and membranes.

In a mixing bowl, combine the shredded Chihuahua and Oaxaca cheeses and fill each pepper with the cheese mixture.

Separate the yolks from the egg whites and beat the egg whites until stiff peaks form.

Gently fold the egg yolks into the whipped egg whites using a spatula.

Lightly dust each stuffed pepper with all-purpose flour, then dip into the batter.

Heat vegetable oil over medium heat, then fry the battered peppers for about 3-4 minutes on each side.

Remove the Chiles Rellenos from the oil and drain on a paper towel-lined plate.

Serve by topping the Chiles Rellenos generously with tomato-based sauce, garnishing with cilantro, and pairing with rice and beans.