Preheat the oven to 425° F. Line a sheet pan with foil or parchment paper.
Place diced pumpkin, onion wedges and carrot pieces on the prepared sheet pan. Drizzle with olive oil and sprinkle with sea salt and pepper. Toss lightly to coat veggies with oil. Roast for 20 minutes or until veggies are beginning to turn golden, stirring halfway through.
While the veggies are roasting, heat the 1 tablespoon butter and olive oil in a large Dutch oven or soup pan over medium heat. When the butter is melted add garlic, ginger, coriander, cumin and red pepper flakes. Cook for 30 seconds, stirring continuously.
Add the chicken broth, potato, cilantro, honey and roasted veggies. Bring to a boil then reduce to a steady simmer. Simmer, uncovered for 15-20 minutes or until potatoes are tender.
Blend with an immersion blender till silky smooth or blend in batches in a regular blender*.
If using a regular blender, return soup to pot, add Greek yogurt and whisk until smooth. If soup is too thick, add more chicken stock.
Taste and season, if needed with more sea salt and pepper. Serve hot with a swirl of Ginger Cream (see below), a scatter of toasted pine nuts** and a sprig of fresh cilantro.
For the Ginger Cream, combine all ingredients and stir until well combined. Add a few small dollops on top of each soup serving and swirl with a toothpick or skewer for a pretty pattern.