Preheat oven to 400ºF. Line rimmed baking sheets with parchment paper.
Add diced pumpkin, 2 tbsp oliveoil, and toss to coat. Sprinkle with koshersalt and blackpepper, to taste. Roast for 30-40 minutes, or until the squash is fork tender. Remove from the oven and set aside.
Add the remaining tablespoon of oliveoil to a large soup pot or Dutch oven and heat over medium-high heat. Add the onions and minced sage, cook until the onions are soft and translucent, about 10 minutes.
Add the diced apples and season with koshersalt and pepper, cook for another 5 minutes, until apples begin to break down a little. Add the garammasala spice mix, roastedpumpkin chunks, chickenstock, and season to taste with koshersalt and pepper. Turn the heat to medium-low and simmer the soup for 10 more minutes. Remove from the heat.
Using an immersion blender, blend the soup until it is a puree and no longer chunky. Return to the burner over medium-low heat, and add the half and half. Stirring occasionally until warmed through, about 3-4 minutes.