Preheat the oven to 375 degrees. Mix the sweet potatoes and cinnamon and place in a single layer in a baking pan. Bake the sweet potatoes for 20-25 minutes or until they are fork tender. Set aside.
Soak the lentils in water mixed with 1 tsp of salt. There should be enough water to cover the lentils by an inch. Set aside for 30 minutes. This helps the lentils better hold their shape when they're cooked (a trick I picked up from watching America's Test Kitchen)
Drain and wash the lentils and place them in a pot. Add 2 cups of water and bay leaves. Bring the lentils to a boil over medium heat, cover and cook until lentils are tender but still hold their shape. This took me under five minutes, so be sure to check your lentils frequently so they don't turn mushy.
To cook the quinoa, wash the quinoa and let it drain thoroughly. In a dry skillet, roast the quinoa until you get a nutty fragrance (also a trick learned from America's Test Kitchen). Add 1 cup of water to the quinoa, bring to a boil, lower the heat to the lowest point on your stove, and cook 15 minutes. Turn off the heat.
Heat the olive oil or vegetable stock in a large saucepan. Add the onions, carrots and celery and a pinch of salt and some ground black pepper. Cook, stirring, for about 8 minutes or until the onions turn soft and the carrots are cooked a bit but still have a bite.
Add the garlic. cumin and ed chilli flakes and saute for another minute.
Add the green peppers and continue to saute until the peppers are just tender, about 2-3 minutes.
Add the roasted sweet potatoes, quinoa, lentils and lemon juice and mix everything thoroughly. Stir in the basil.
Serve hot or warm.