Preheat your oven to 190°C (375°F). Lightly oil a baking dish and set aside.
Slice the tops off the bell peppers and carefully scoop out the seeds and membranes, making space for the filling. Place them upright in the baking dish.
In a sauté pan, heat the olive oil over medium heat. Add diced onion and minced garlic, cooking until fragrant and translucent, about 5 minutes. You’ll notice a pleasant aroma and the onions becoming slightly golden.
Add the chopped mixed vegetables to the pan and cook for another 3-4 minutes until they soften slightly but still retain some crunch.
Stir in the rinsed quinoa, drained beans, cumin, smoked paprika, and cinnamon. Cook for another 5 minutes, stirring occasionally, until everything is heated through and fragrant. The mixture should be slightly thickened and well combined.
Remove the pan from heat and stir in half of the chopped parsley and cilantro, along with lemon zest and a squeeze of lemon juice. Season with salt and pepper to taste, adjusting the flavors as needed.
Using a spoon or piping bag, gently stuff each pepper with the filling, pressing softly to pack it in without overflowing. Place the stuffed peppers upright in the baking dish.
Bake the peppers in the preheated oven for about 20-25 minutes, until they are tender and the filling is bubbling and slightly golden on top. You may want to rotate the dish halfway through for even baking.
Remove the dish from the oven and let the peppers rest for 5 minutes. This helps the flavors settle and makes them easier to handle.
Garnish the peppers with the remaining chopped herbs, a drizzle of olive oil, and an extra squeeze of lemon if desired. Serve warm and enjoy the vibrant flavors and tender texture!