Roasted Yams and Apple Soup

We served a version of this recipe at the Redlands Conservancy Feasting on the Farm Event last evening, but we used Cinderella Pumpkins instead of Yams and everyone seemed to love it!
Roasted Yam and Apple Soup

2-3 lbs yams (or 1 Cinderella pumpkin cut in half, roasted)
1-2 tbsp olive oil
2 large yellow onions, diced
1 shallot, diced
2 celery stalks, diced
2 green apples, such as granny smith, peeled and thinly sliced
Kosher salt to taste
Ground pepper to taste

Preheat oven to 400 F. Prick through skins of yams with fork, place on baking sheet and roast until tender, approximately 45-60 minutes. Rotate yams ½ way through cooking. On stovetop, heat oil in large pot over medium-high heat. Add onion, celery, shallots, and apple and cook until onions are translucent. Stir occasionally, cook12-15 minutes. Don’t burn or brown onions. Remove yams from oven; cut each in half and scoop out soft flesh with spoon. Set peels aside. Add the cooked flesh to pot with onions, celery, and apples. Add 6 cups water, 2 tsp salt, ½ tsp ground pepper. Bring back to low simmering heat, stirring frequently. Use immersion blender on stovetop or place in blender or food processor and puree. If using blender or food processor, blend in batches then return to pot on stovetop. Add water if necessary to reach desired consistency. Serve hot with finely diced apples to garnish.