Add the olive oil to a large pot and heat over medium-high heat. When the oil is hot, add in the onion, celery, sweet potatoes and garlic. Season with cumin, salt and pepper. Sauté the vegetables for about 4-5 minutes then add in the chopped chipotle chile and adobo sauce, vegetable broth and water. Stir everything together then reduce the heat to low, cover with a lid and simmer for 20 minutes, or until the sweet potatoes are very soft (fork tender).

While the soup is cooking, make the spiced pepitas. Toss all of the ingredients together in a small bowl. Heat a skillet over medium heat and add in the pepitas. Stir the pepitas occasionally and toast them until they're lightly browned, puffed and fragrant.

Use an immersion stick or blender to purée the soup until it's completely smooth. Pour in the half and half and Greek yogurt and immediately stir the soup until they're incorporated.

Serve the soup topped with the spiced pepitas, chopped cilantro and an extra drizzle of Greek yogurt and/or adobo sauce.