Heat olive oil in a large soup pot over medium heat until it shimmers. Add the onion, leeks, carrots, and celery and saute until soft, about 10 minutes. Resist the urge to stir frequently, so the veggies caramelize rather than steam.
Add the garlic, turmeric, cumin, and a pinch of salt and saute for a minute.
Add in butternut squash and stock. Simmer for 20 – 30 minutes until butternut squash is soft (cook time will vary depending on the size of your butternut squash cubes). Season with salt and pepper to taste.
Turn off heat and use an immersion blender to puree soup until velvety smooth. Alternately, you can cool slightly and puree in batches using a traditional blender.
Top with a sprinkling of hemp hearts (optional).