Place the chopped apples, cinnamon, and a pinch of salt into a large pot. Sauté over medium heat for about 5 minutes, stirring occasionally, until the apples begin to soften and release their aroma.
Pour in the apple cider and bring the mixture to a gentle simmer. Reduce heat to low and cover the pot, letting it cook for about 10-15 minutes until the apples are tender and the flavors meld.
Use an immersion blender to carefully blend the cooked apples until the mixture is smooth and velvety, with no lumps remaining. Be cautious of splattering hot liquid.
Add the chili oil to the blended soup, stirring well to incorporate. Taste and adjust the level of heat by adding more chili oil if desired.
Bring the soup back to a gentle simmer for an additional 2-3 minutes to let the flavors meld and the heat infuse. The soup should be warm and fragrant, with a slight spicy kick.
Serve the soup hot in bowls, garnished with a sprinkle of cinnamon or a drizzle of chili oil for extra flavor. Enjoy the smooth, warm, and spicy-sweet soup immediately.
