For the soup: Heat the oil in a large pot over medium heat. Add the onion, celery, and ginger and sauté until the onion is tender and translucent, about 8 minutes. Stir in the broth, carrots, potato, and curry powder and bring to a boil. Decrease the heat to maintain a simmer. Cook, stirring occasionally, until the carrots are tender, about 25 minutes. Using an immersion blender (or using a regular blender and working in batches), blend until completely smooth. Put the pot over low heat and cook, stirring often, until heated through. Stir in 1/3 cup of the cashew cream.
For the cashew cream: Put the cashews in a food processor or high-speed blender and pulse a few times to grind them up. Add the lemon juice and salt. With the motor running, drizzle in the water and process until completely smooth (which may take a few minutes), stopping occasionally to scrape down the sides of the work bowl or blender jar. Add more water for a thinner consistency, if desired; you may want it as thick as whipped cream or as thin as coconut milk, depending on how you plan to use it. (store extra in a covered container in the refrigerator)
for the quinoa: add quinoa to a dry skillet over medium heat. Toss until quinoa begins to pop and get brown. While quinoa is popping, whisk together remaining ingredients. Once quinoa is toasted, about 1 minute, remove from heat and stir in olive oil-garlic paste. Stir to completely combine then set aside.
to serve: transfer soup to bowls then garnish with a touch more cashew cream and a sprinkle of quinoa. Enjoy!