Preheat broiler and line a baking sheet with foil. Place the poblano peppers on the pan and broil for 8-10 minutes, flipping halfway through, or until the skin is black and charred. Transfer the peppers to a large bowl and cover with foil and let rest for 10 minutes. Covering the bowl traps the steam inside and making it easier for the skin to separate.
After 10 minutes, carefully peel the skin off of each pepper (you can use a spoon to carefully scrape the peeling as well). Then with a spoon, cut open one side of the pepper and carefully remove the stem and the seeds. Repeat for all of them and set aside.
For the Monterey cheese, slice 4 or 6 1-inch pieces, depending on how many peppers you have. Shred the remaining amount.
Lay the peppers flat open and place a slice of cheese in each one. Roll the peppers closed and set aside.
In a mixing bowl on medium speed, whisk the egg whites for 3-5 minutes or until soft peaks form. Beat the egg yolks and add into the mixing bowl. With a spatula, carefully fold in the yolks until well combined. Set aside.
In a medium nonstick skillet over medium heat, add the chorizo. Break apart and cook for 1-2 minutes or until it begins to crumble.
Add half of the egg mixture in an even layer into the pan and over the chorizo.
Arrange the rolled peppers on top of the eggs mixture. Then sprinkle some of the remaining shredded cheese on top of the peppers.
Pour the rest of the egg mixture over the peppers into an even layer. Sprinkle the rest of the shredded cheese on top of the formed mixture.
Arrange the cubes of butter along the edge of the pan and reduce the heat to medium-low.
Cover the pan with a lid and cook for 10 minutes or until the sides are golden brown.
Turn off the heat and leave the skillet with the lid on for 5-10 minutes or until the top of the frittata is cooked.
Season with salt, pepper and cilantro. Serve with hot sauce or choice of toppings.
