Begin by dicing the onion and mincing the garlic.
If using, brown the ground meat in a skillet over medium-high heat until fully cooked and browned, then drain excess fat.
Add the diced onion and minced garlic to the slow cooker, along with the cooked meat if using. Stir to combine.
Pour in the drained black beans, diced tomatoes with juice, and pumpkin puree. Add the broth, chili powder, cumin, cinnamon, and a pinch of salt and pepper.
Stir everything together until well combined, ensuring the spices are evenly distributed.
Cover the slow cooker with its lid and set to low for 4 hours, allowing the flavors to meld and the chili to thicken.
Once cooking is complete, give the chili a good stir and taste, adjusting salt, pepper, or spices as needed.
Serve hot, garnished with your favorite toppings like sour cream, shredded cheese, or chopped cilantro, if desired.