
Heat the oil in a Dutch oven over medium heat until shimmering. Add the onion, celery, jalapeño, and garlic, and cook until soft, 6 to 8 minutes. Add the cocoa powder, chili powder, cumin, paprika, salt, and pepper, and stir to combine. Cook for 2 minutes, stirring frequently to ensure the spices don’t burn. Stir in the molasses and lentils and cook for a minute more.
Add the tomatoes, broth, and beans, and stir to combine. Bring to a boil, then reduce the heat to low and simmer for 30 minutes, stirring occasionally to prevent the chili from sticking to the bottom of the pot.
Serve topped with avocado, scallions, and jalapeño, if desired.