Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Add ground beef, breaking it up with a wooden spoon, until browned, 6-7 minutes.
Reduce heat to medium. Add the diced shallot and bell pepper to the pot. Sauté for 4-5 minutes until softened. Stir in the minced garlic, chili powder, cumin, smoked paprika, and salt. Cook for 1 minute until fragrant.
Pour in the pumpkin puree, diced tomatoes with their juices, rinsed black beans, and beef broth. Stir well. Bring to a low boil, then turn the heat to low, cover, and gently simmer for at least 20 minutes (or up to several hours) to allow the flavors to meld.
Remove the lid and stir in the chopped spinach until wilted. Taste and adjust seasonings if desired. Ladle chili into bowls and top generously with pumpkin seeds.
Notes
Substitutions - Ground turkey can be substituted for beef. Vegetable or chicken broth can be used in place of beef broth, and spinach can be omitted for a more traditional-style chili. Using bone broth can increase the protein content.
Pumpkin puree - Do not buy pumpkin pie filling. Just plain pumpkin puree. I like Libby or non-organic brands as I find the flavor and texture to be much smoother and more flavorful.