Begin by cooking the brown rice according to package instructions. Typically, this involves rinsing the rice, then boiling it in water (about 2 cups of water for 1 cup of rice) until tender. Once done, set it aside and fluff with a fork.
While the rice is cooking, preheat your oven to 425°F (220°C). On a baking sheet, toss the sliced plantains with 1 tablespoon of olive oil and a pinch of salt. Arrange them in a single layer and roast for about 15-20 minutes, flipping halfway through, until golden brown and caramelized.
On the same baking sheet (after removing the plantains), toss the sliced bell peppers and red onion with the remaining tablespoon of olive oil, 1/2 teaspoon of salt, and 1 teaspoon of ground cumin. Roast for about 15-20 minutes until they are tender and slightly charred.
In a large skillet, heat over medium heat. Add the jalapeño and sauté for about 2 minutes until fragrant. Then, add the minced garlic, tomato paste, and remaining spices (2 teaspoons cumin, 1/4 teaspoon allspice, and dried oregano). Stir everything together and cook for another minute.
Add the black beans to the skillet, stirring to combine with the spice mixture. If you’re using canned beans, be sure to rinse and drain them first. Let everything simmer for about 10 minutes, allowing the flavors to meld together.
To serve, place a generous scoop of rice on each plate. Top with the black bean mixture, followed by the roasted peppers and onions. Garnish with roasted plantains, sliced radishes, diced avocado, and fresh cilantro. Serve with lime wedges on the side for an extra burst of flavor.