Spicy Roasted Sweet Potato Lentil Soup (gf)

This soup is built on a base of roasted vegetables which adds depth of flavour. This part could also be done ahead. You could use a bit of tomato paste if the tomatoes look terrible. If using yellow or red lentils, check after 15 minutes or so. They cook much more quickly.

1 lg sweet potato, rough chopped
2 sm red onion, rough chopped
4 Roma tomato, halved
3 cloves garlic, peeled and chopped
½ t chili flakes
2 t ground cumin
kosher salt and fresh-cracked black pepper
4 c stock (use vegetable stock if you prefer a vegetarian soup)
1 c green or brown lentils
plain yogurt and cilantro or parsley to garnish

Preheat oven the over to 350ºF. Toss the potato, onion, tomato and garlic in a scant amount of oil and season with salt and pepper, chili flakes and cumin, and place on a sheet pan. Cover with foil and bake for 1 hour or until vegetables are tender and golden. Transfer roasted vegetables to a large pot and pour in 1 cup stock. Blitz until smooth then bring to the boil. Add the lentils and the rest of the stock, reduce the heat to low and simmer, covered, for about 30 minutes or until lentils are tender. Check seasoning. Serve, topped with a dollop of yogurt and some parsley. Serves 4.