- 2 pounds carrots, peeled and chopped into 1-inch chunks
- 1 pound celery, chopped into 1-inch chunks
- 1 pound yellow onions, halved, peeled, and cut into 1-inch chunks
- 3 tablespoons canola oil, divided
- 1 1/2 teaspoons kosher salt, divided
- 1/4 cup mellow white miso, divided
- Heat the oven to 425°F. Line two sheet trays with silicone mats or parchment.
- Add the carrots to one tray. Drizzle with 1 tablespoon oil and 1/2 teaspoon salt. Toss with your hands. Add the celery and onion to another tray. Drizzle with the remaining 2 tablespoons oil and sprinkle with 1 teaspoon salt. Toss with your hands.
- Stick both trays in the oven and roast for about 1 hour total. Every 20 minutes, rotate the trays and stir vegetables to encourage even cooking.
- When the vegetables are done remove both trays from the oven. Add about half of each tray to a blender. Add 2 tablespoons miso and 4 1/2 cups water. Blend until completely smooth, then pour into a large pot on the stove. Repeat with the remaining vegetables, remaining 2 tablespoons miso, and another 4 1/2 cups water—blended until smooth, poured into the pot.
- Season the soup with salt, if necessary. Thin with more water, if necessary, depending on how thick you like your soup. Warm over medium-low heat, stirring often, until it’s the temperature you like to eat your soup. Pour into a bowl and serve.