Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add diced onion, celery, and jalapeno, sautéing for 5–7 minutes until they are softened and fragrant. Stir in cumin and minced garlic, allowing the mixture to cook for an additional minute until the garlic is aromatic. Then, incorporate drained diced tomatoes and let everything simmer for about 5 minutes.

Stir in 1 cup of rinsed quinoa and 1 can of black beans into the skillet mixture. Pour in 2 cups of water (or vegetable broth for added flavor), stirring to combine well. Cover the skillet with a lid and let it simmer for 20 minutes on low heat, until the quinoa is fluffy and the water is absorbed. Once cooked, add shredded cheese and mix until it's melted and creamy.

Preheat your oven to 350°F (175°C). While the oven heats, take a baking dish and pour in any reserved liquid from the diced tomatoes to keep the dish moist.

Carefully slice the tops off 4–5 bell peppers and remove the seeds. Place the bell pepper halves upright in the prepared baking dish. Generously spoon the quinoa mixture into each pepper, packing it in to ensure they are filled to the brim. Cover the dish with aluminum foil to help them steam.

Put the baking dish in the preheated oven and bake the stuffed peppers for 40 minutes, or until the peppers are tender and begin to wrinkle. After 35 minutes, you can remove the foil if you prefer a little browning on top.

Allow the healthy quinoa stuffed peppers to cool for about 5 minutes before serving. Drizzle any pan juices over the tops to enhance the flavor, and feel free to garnish with fresh herbs or avocado slices for extra flair.