These seriously are the best chicken enchiladas ever. And it’s all due to a very special (and easy) homemade tomato cream sauce that will knock your socks off.
For fresh tomatoes: Roast the tomatoes and chiles on a baking sheet 4 inches below a very hot broiler, until they're darkly roasted.
If using canned tomatoes: In a small dry skillet, roast the chiles over medium heat, turning regularly, until they're soft and splotchy-black, about 5 minutes. Place in a blender or food processor along with the drained canned tomatoes. Blend to a smooth puree. I like to roast the poblano peppers over my stovetop gas flame.
In a 4-5 quart Dutch oven, heat the oil or lard over medium heat. Add the onion and cook, stirring regularly, until golden, about 7 minutes.
Raise the heat to medium-high, and stir in the tomato puree. Cook, stirring, until darker in color and thickened to the consistency of tomato paste, about 10 to 15 minutes.
Stir in the broth, partially cover and simmer 15 minutes. Taste and season with salt, usually about 1/2 teaspoon. The sauce should be a slightly soupy consistency—not as thick as spaghetti sauce. If it is too thick, stir in a little additional broth. Keep warm over low heat.
Stir the crema into the sauce. Put the chicken in a bowl and stir 1/2 cup of the sauce mixture into it. Taste and season with additional salt if you think it needs it.
Heat the oven to 350°. Smear about 1/4 cup of the sauce over the bottom of a 13x9-inch baking dish.
Lay the tortillas out on a baking sheet (2 sheets if you have them, for more even heating), and lightly brush or spray both sides of the tortillas with oil. Bake just to warm through and soften, about 3 minutes. Stack the tortillas and cover with a towel to keep warm.
Working quickly so the tortillas stay hot and pliable, roll a portion of the chicken into each tortilla, then line them all up in the baking dishes. Douse evenly with the remaining sauce, then sprinkle with the cheese.
Bake until the enchiladas are hot through (the cheese will have begun to brown), about 15 minutes.
Garnish with onion rings and cilantro sprigs. These are best served piping hot from the oven.