Step 1

Prepare pickled onions: Thinly slice the onions and put into a pickling jar or a small bowl. In a separate microwavable bowl or measuring cup, mix the two vinegars and microwave for two and a half minutes. Meanwhile, toss the garlic, mustard, and salt and pepper in with the onions. Pour the hot vinegar over the onion mixture and allow to sit at room temperature for a few hours. Serve or refrigerate for up to a few weeks.

Step 2

Make the sauce: In a blender, combine the habaneros, cheese, milk, onion, and garlic. Season with salt and pepper, and blend until smooth.

Step 3

Build the casserole: Remove the skin from the plantains. Slice the plantains the long way. Build the casserole almost like a lasagna, laying down sheets of plantain, then alternating with cheese sauce and black beans. Top with the rest of the cheese and bake at 350°F for an hour and a half. Depending on how ripe your plantains are, you might need more or less time. Stick a knife into the center and if it goes in smoothly, the casserole is done.

Step 4

Allow to cool 15 minutes before slicing. Top with the pickled onion and some chopped cilantro and serve.