Preheat your oven to 400°F (200°C). Toss the cubed sweet potatoes with a tablespoon of olive oil, salt, and pepper, then spread them evenly on a baking sheet. Roast for about 25-30 minutes, until golden and tender, shaking the pan halfway through.
While the sweet potatoes roast, heat a tablespoon of olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion and sauté until it becomes soft and translucent, about 5 minutes, filling your kitchen with a sweet aroma.
Add the minced garlic to the onions and cook for another minute until fragrant, listening for a gentle sizzling sound and watching for the mixture to become more aromatic.
Increase the heat slightly and add the ground turkey to the pot. Break it apart with a spoon and cook until no longer pink, about 7-8 minutes, until it starts to brown slightly and emits a savory smell.
Pour in the apple cider and stir, scraping up any browned bits from the bottom of the pan. Let it simmer gently for 2-3 minutes until it reduces slightly and blends with the turkey and onions.
Sprinkle in the cinnamon and cumin, stirring to distribute the warm spices evenly through the mixture. Watch as the mixture turns fragrant, about 1 minute.
Stir in the diced tomatoes with their juice, then add the drained kidney beans if using. Bring the mixture to a gentle simmer, then reduce the heat to low and cover loosely. Let it cook for 15 minutes, allowing flavors to meld.
Check the roasted sweet potatoes; they should be tender and beginning to caramelize on the edges. Add these roasted sweet potatoes to the chili, stirring gently to combine and heat through for another 5 minutes. Adjust seasoning with salt and pepper if needed.
Uncover the pot and let the chili simmer uncovered for a few minutes to thicken slightly and intensify the flavors, making sure the sweet potatoes remain vibrant and tender.
Once thickened and heated through, taste test and adjust the seasoning if necessary. Serve the chili hot, garnished with your favorite herbs or a dollop of sour cream if desired.