Preheat oven to 400°F (200°C).
Cut peeled sweet potatoes into cubes. On a baking sheet lined with foil or parchment, toss cubes with a drizzle of oil and seasonings.
Roast 30-40 minutes, until soft and starting to brown.
While sweet potatoes roast, add 1½ cups water to a saucepan over medium-high heat and bring to a full boil.
Add 1 cup uncooked green lentils to boiling water and cook 2-3 minutes (or according to package directions).
Reduce to medium-low heat and simmer 20-30 minutes.
When finished simmering, drain and set aside.
In a separate saucepan over medium heat, add oil, onion, celery, and carrot. Cook for 2-3 minutes, until onions start to sweat.
Add garlic, ginger, and seasonings. Cook another minute.
Add roasted sweet potato and coconut milk. Bring to a boil and turn down to a simmer for 20-25 minutes.
Enjoy the soup as is, or you can use a blender for a creamier soup!
Pour contents of sauce pan into a blender, blend to desired consistency, and return blended mixture to saucepan. Or, use an immersion blender to blend the soup in the sauce pan.
Once soup reaches desired consistency, stir in cooked and drained lentils.
Serve topped with nondairy yogurt of choice, and garnish with cilantro!
Yields ~8 cups sweet potato coconut curry lentil soup.