Roast the poblanos: Preheat oven to 400°F (200°C). Place poblanos on a baking sheet and roast for 10 minutes until skins blister.
Peel and prep: Let peppers cool, then remove skins, seeds, and stems. Slice into strips.
Sauté the aromatics: Heat oil in a skillet over medium heat. Cook onions and garlic for 3 minutes. Add cumin, smoked paprika, salt, and pepper.
Assemble the filling: Stir in cooked beef (or beans), corn, and half the cheese. Remove from heat.
Mix the batter: In a bowl, whisk eggs, sour cream, milk, flour, and baking powder until smooth.
Layer the casserole: In a greased baking dish, spread half the batter. Add a layer of poblano strips and beef mixture. Repeat.
Top and bake: Sprinkle remaining cheese on top. Bake at 375°F (190°C) for 30 minutes or until golden and set.
Serve: Let cool for 5 minutes, then slice and enjoy.