
Preheat the oven to 450℉ and line a rimmed baking sheet with tinfoil.
In a large bowl, stir together the carrots, onions, and celery. Stir in the 2 Tablespoons olive oil, 1 Tablespoon Kosher salt, and dash of freshly ground black pepper. Pour the vegetables onto the baking sheet and bake the veggies for 1 hour or until roasted and soft.
In a large stockpot, melt the butter. Stir in the garlic and thyme and stir for 1 minutes. Stir in the roasted veggies and toss for 1 minute.
Stir in the the water and broth and bring to a boil. Simmer for 40 minutes. Remove from heat.
Using an immersion blender, blend the soup until smooth and creamy. Stir in the half and half and reheat the soup until ready to serve. Add salt and pepper, to taste, before serving. Garnish with roasted and salted sunflower or pumpkin seeds.