Preheat the oven to 400°F (200°C). Spread the sweet potato chunks on a baking sheet, toss with a little olive oil, and season with salt. Roast for about 25-30 minutes, until tender and lightly caramelized, stirring halfway through. The sweet potatoes should be soft and golden.
Meanwhile, heat a tablespoon of olive oil in a large pot over medium heat. Add the diced onion and cook, stirring frequently, until translucent and fragrant, about 5 minutes. You should see it become soft and slightly golden.
Add the minced garlic and cook for another minute until fragrant—listen for it to become aromatic and see it turn slightly golden.
Stir in the ground turkey, breaking it apart with your spoon or spatula. Cook until it browns evenly and loses its pink color, about 7-8 minutes. The meat should be no longer pink and develop a slightly crispy exterior.
Add the chili powder and cinnamon to the turkey and stir well, cooking for another minute to toast the spices and release their aroma.
Pour in the diced tomatoes with their juices and the broth. Stir to combine, scraping up any browned bits from the bottom of the pot. Bring the mixture to a gentle simmer and let cook uncovered for 10 minutes to develop flavors.
Once the sweet potatoes are roasted and tender, carefully add them into the chili. Gently fold in the sweet potatoes so they absorb some of the spicy broth without breaking apart.
Continue simmering the chili for another 10 minutes, allowing the sweet potatoes to meld and the flavors to deepen. Adjust salt and pepper to taste.
Serve the chili hot in bowls, garnished with fresh herbs or a sprinkle of cheese if desired. The dish should be thick, hearty, and bursting with warm autumn flavors.
