When I was just out of college and my cooking repertiore was still pretty limited, I used to make a casserole beans and tomatoes layered with corn tortillas and cheese, a recipe my mom used to make from one of her Williams-Sonoma cookbooks. As tasty as it was, my roommate Leslie and I doubted its authenticity as a Mexican dish. It just seemed to us a bit like something out of The Family Circle Illustrated Library of Cooking, and we dubbed it Fiesta Casserole.

Perhaps this recipe was a little more authentic than we gave it credit for, because this week I picked up a copy of Rick Bayless’s Mexican Kitchen and found a couple different variations on this theme. This one is rich and smokey, and tastes almost chocolatey, like mole, even though there’s no chocolate in it. It will take you the better part of an afternoon to make, but it’s definitely worth it.

Layered Pasilla-Tortilla Casserole with Black Beans and Thick Cream
Adapted (with a few changes) from Rick Bayless’s Mexican Kitchen

For the sauce:
1 small head of garlic, separated into individual cloves but not peeled
6 whole dried pasilla chiles (also called chile negro), stems removed
1 teaspoon dried oregano
1/4 teaspoon freshly ground black pepper
1/8 teaspoon ground cumin
1 tablespoon olive oil
1 1/2 cups chicken or beef broth
Salt to taste

For the beans:
1 tablespoon olive oil
1 small onion, diced
2 cups cooked, seasoned black beans, preferably from dried beans, not canned. (I cook mine with a small onion cut into large chunks, a bay leaf, and a piece of dried New Mexico chile. Make some extra. You can freeze the leftovers.)
Salt to taste

For the casserole:
12 corn tortillas
1/2 cup Mexican crema (or sour cream or crème fraîche)
1/2 cup Oaxaca cheese, shredded

A few leaves of cilantro
1 avocado, sliced (optional)

To make the pasilla chile sauce: Roast the garlic cloves in an ungreased skillet over medium heat, turning frequently, until the garlic is soft and the skins are charred. Transfer garlic to a bowl, and peel it once it is cool enough to handle. While the garlic is roasting, add the chiles to the skillet a few at a time and cook a couple minutes on each side, until they are slightly charred. Put the chiles in a bowl and pour enough boiling water over them to cover them completely. A small plate or bowl on top of the chiles will help keep them submerged. Let the chiles soak for about 30 minutes, or until soft. Drain the chiles, reserving 1/3 cup of the soaking liquid.

Place the peeled garlic cloves, chiles, oregano, pepper, cumin, and reserved liquid in a food processor or blender and purée until smooth. Push the purée through a mesh sieve set over a bowl. The skins and seeds from the chiles will remain in the sieve, and you’ll have a nice smooth paste in the bowl.

Heat a tablespoon of olive oil in a small saucepan over medium high heat. Add the chile paste and cook, stirring constantly, until the chile paste is very thick and dark. It will look like chocolate. Add the broth and simmer, partially covered, for about 30 minutes. Season with salt to taste.

Meanwhile, heat another tablespoon of oil in a skillet and cook the onion with a pinch of salt until lightly browned. Add the beans along with about 1/2 cup of their cooking liquid (or water or broth of you don’t have much cooking liquid.) Mash beans with a potato masher, adding additional liquid if necessary. The mashed beans should be loose but not soupy. Remove from heat and season with salt to taste.

Heat oven to 350 degrees. Lightly oil the tortillas and toast, one or two at a time, in a skillet over high heat, until lightly browned. Ladle some of the sauce into an 8 or 9 inch square baking dish, enough to cover the bottom. Add a layer of three tortillas, cutting them as necessary to more or less fit the pan with one layer. Two whole tortillas plus two halves should do the trick. Spread half the beans over the tortillas, then add another layer of tortillas. Spread with another layer of sauce, followed by half of the sour cream and half of the cheese. Repeat with the remaining ingredients: tortillas, beans, tortillas, sauce, sour cream, cheese. Bake, uncovered, until the cheese is melted and the sauce is bubbling, about 20 minutes. Let it set up for a few minutes once it comes out of the oven, then cut into squares. Garnish with cilantro leaves and serve with avocado slices along side.