Step 1: Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Step 2: Toss the cubed sweet potatoes and apples with olive oil, salt, and pepper on the baking sheet until well coated.
Step 3: Roast for 30-35 minutes, or until the sweet potatoes are tender and starting to brown at the edges.
Step 4: In a large pot or Dutch oven, sauté the onion in a splash of olive oil over medium heat until translucent, about 5 minutes.
Step 5: Add the garlic and ginger to the pot and cook for another 1-2 minutes until fragrant.
Step 6: Stir in the roasted sweet potatoes, roasted apples, cinnamon, and vegetable broth.
Step 7: Bring the mixture to a boil, then reduce heat and simmer for 10 minutes to allow the flavors to meld.
Step 8: Use an immersion blender to blend the soup until completely smooth. Alternatively, transfer to a standard blender in batches.
Step 9: Season with additional salt and pepper if needed. Serve hot, garnished with fresh thyme and pumpkin seeds.