In a large bowl, combine the eggs with the salt, pepper, chile powder, and cilantro. Whisk with a fork until evenly blended and set aside.
In a 10-inch non-stick skillet, heat the olive oil over medium heat. Add the onion and saute for 5 to 6 minutes, stirring occasionally, until softened and slightly golden. Add the red pepper and the poblano and cook for 2 minutes more. Pour the egg mixture into the pan and swirl the bottom of the pan with a fork to mix the vegetables with the eggs. Reduce the heat to medium-low, scatter the cheese over the top and cook the frittata slowly, covered, until the eggs are set almost all the way through. Shake the pan back and fourth on the burner occasionally to be sure the frittata is not sticking. Place the pan under a broiler on medium for a minute or two just to set the top of the frittata completely. Remove from the heat and let the frittata set in the pan for 10 minutes. Place a round platter on the top of the pan and invert the frittata onto it. Garnish with sprigs of cilantro and serve warm or at room temperature, cut into wedges.
c.1997, M.S. Milliken & S. Feniger, all rights reserved