Preheat your oven to 180°C (350°F). Slice the tops off the bell peppers and carefully scoop out the seeds and membranes, creating a hollow cavity for the filling.
Heat the olive oil in a skillet over medium heat. Add the chopped onion and minced garlic, sautéing until fragrant and slightly translucent, about 3-4 minutes, with a gentle sizzle and a lovely aroma filling the kitchen.
Add the diced vegetables to the skillet and cook until tender and slightly charred around the edges, about 5 minutes, stirring occasionally. The vegetables should become fragrant and colorful.
In a large mixing bowl, combine the cooked grains, sautéed vegetables, cooked beans or lentils, chopped herbs, smoked paprika or cayenne (if using), and a pinch of salt and pepper. Mix well until evenly combined, tasting and adjusting seasoning as needed.
Using a spoon or spatula, stuff each hollowed pepper with the filling, pressing gently to pack it in without overflowing. Place the stuffed peppers upright in a baking dish.
Bake the peppers uncovered in the preheated oven for about 30 minutes, until the peppers are tender and slightly charred at the edges, and the filling is bubbling with flavor.
Remove the dish from the oven and let the peppers rest for 5 minutes to allow the filling to settle. Garnish with extra chopped herbs or a squeeze of lemon if desired.
Serve the vibrant peppers warm, alongside a fresh salad or crusty bread for a complete meal that’s as colorful as it is flavorful.