Remove the stems and slice the peppers on one side lengthwise, leaving the peppers intact, and then remove the seeds.
Preheat the oven to 400 degrees Fahrenheit and line a large baking pan with aluminum foil or parchment paper.
Place the Poblano peppers on the baking pan evenly spaced, then drizzle on the olive oil. Use your hands to coat them well.
Bake for 20 minutes. Flip the peppers over and bake for 10 more minutes or until the tops have charred a bit.
In the meantime, whisk together the eggs, milk, flour, salt, cumin, paprika and baking powder in a large bowl then set aside.
Once the peppers are done, reduce the oven heat to 350 degrees Fahrenheit.
Let the peppers cool until you can safely handle them then remove the skin and slice each pepper in thirds lengthwise.
Pour 1/3 of the egg mixture into a 9 by 13-inch baking pan or a casserole dish then add ½ of the peppers on top along with 1/3 of the cheese sprinkled on top.
Pour half of the remaining egg mixture on top followed by the remaining pepper slices.
Pour on the remaining egg mixture followed by the remaining cheese and cover loosely with aluminum foil then bake for 20 minutes.
Remove the foil and bake again for 15-20 minutes or until the center no longer jiggles.
Slice and serve with freshly chopped cilantro for garnish if desired.
Notes
Roast the peppers ahead of time. Peeling the peppers can be a tedious task, especially if it's your first time. You can roast and peel the poblano peppers, and refrigerate until you are ready to bake the dish.
Use gloves to peel the peppers. As with all peppers, handle them with care. Even though poblanos are considered mild peppers, they can still irritate your soft tissues (nose and eyes). Using gloves keeps the pepper from getting on your fingers.