Heat the large stockpot over medium heat and add the olive oil, allowing it to shimmer and warm up.
Sauté the finely chopped onion until it turns translucent and starts to sweeten, about 5 minutes. Let it fill your kitchen with a gentle aroma.
Add the minced garlic to the pot and stir for about 30 seconds until fragrant; be careful not to let it burn.
Pour in the pumpkin puree and vegetable broth, stirring to combine all the ingredients smoothly. Bring the mixture to a gentle simmer.
Stir in the chili flakes, cinnamon, and cumin, then let the soup simmer uncovered for 20-25 minutes, stirring occasionally. The flavors will meld, and the soup will deepen in color as it thickens slightly.
Remove the pot from heat and carefully blend the soup until silky and smooth, using an immersion blender or transferring to a regular blender in batches—be cautious with the hot liquid.
Stir in the cream to add richness and help achieve a velvety texture; taste and adjust seasoning with salt and black pepper as needed.
Warm the soup gently over low heat just until heated through. The final consistency should be smooth, velvety, and vibrant orange in color.
Ladle the soup into bowls, garnish with a swirl of cream or a sprinkle of chili flakes if desired, and serve hot.