Heat a large pot over medium-high heat. Add onion, celery, bell pepper and carrots with a splash or two of broth, salt and pepper. Cook until veggies soften about 10 minutes.
Add garlic and spices sauté another 5 minutes. Pour broth into pot with sweet potato, split peas and bay leaf.
Turn heat down to medium-low. Simmer 45 minutes covered until split peas begin to soften and pop.
Remove half the soup, place in a blender and pulse to puree. Add pureed soup back to the pot and stir well. Serve immediately and garnish with green onions.
Store the soup in the refrigerator up to 5 days or in the freezer up to 60 days.
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Notes
Use an immersion blender to puree the soup a bit instead of transferring hot soup to a blender.
Bring out more of the flavor in the seasonings by adding them to the aromatics at the beginning to toast them.
Add a pinch of baking soda to your soup to help soften the split peas and make the soup creamier.