Heat oil in a large pot over medium heat. Once hot, add diced onions and sauté, stirring occasionally, for 5–7 minutes or until golden.
Stir garlic and all seasonings into the pot and season with salt and pepper. Continue to sauté 1–2 minutes until fragrant.
Add black beans, tomatoes, stock, and pumpkin. Increase heat to bring the mixture to a boil, then reduce and let simmer with the lid on for 20 minutes.
Stir in cream. If using, add lime juice and cilantro, then mix. Taste and adjust the seasonings as needed. Ladle soup into bowls and serve warm with tortilla chips for dipping!
