Step 1

First, cook the beans. Add the beans to a heavy-bottomed pot or Dutch oven and cover them with water by a few inches. Add the halved onion, jalapeño, cumin seeds, and bay leaf. Bring to a boil and boil for 5 minutes. Reduce the heat to medium low and simmer until the beans are tender but not mushy, about 90 minutes, depending on the age of your beans. (Older beans will take longer to cook.) Add 1 teaspoon salt; simmer for another 5 minutes to dissolve and distribute the salt. Use tongs or a slotted spoon to remove the onion, jalapeño, and bay leaf, and discard them. Drain the beans.

Step 2

Next, make the sauce. In a large, heavy-bottomed pot or Dutch oven, melt the butter over medium heat. Add the diced onion and sauté until translucent, about 5 minutes. Add the garlic and sauté for 1 additional minute. Add the peppers and mushrooms and sauté until they have given up most of their liquid, about 10 minutes.

Step 3

Sprinkle the flour over the vegetables and cook, stirring, until the flour has a chance to lose a bit of its raw flavor, about 2 minutes.

Step 4

Whisk in the vegetable stock and simmer for about 3 minutes, until thickened. Remove from heat.

Step 5

Add the drained beans, Ro-Tel, chili powder, cumin, cayenne, and cream to the sauce. Stir to combine and taste for seasoning.

Step 6

Heat your oven to 375°F. Grease a 9-by-13-inch casserole dish.

Step 7

Build the casserole by sprinkling half the tortilla chips in an even layer at the bottom of the dish. Next, pour half the bean mixture over the chips. Sprinkle about two-thirds of the cheese over the beans. Pour the rest of the beans over the cheese. Then layer the rest of the chips and finish by topping with the remaining shredded cheese.

Step 8

Bake the casserole until browned and bubbling, 20 to 25 minutes. Let rest for 10 minutes and serve.