This is one of my favorite soups, from a Food52 community member. It's done in about 30 minutes: silky, complex, nutritious, and perfect either as a first course or as a meal in itself. Roasting the carrots and infusing the broth with ginger and thyme are the secrets to giving the soup a sweet, earthy depth. Use a quality vegetable stock—since there are so few ingredients here, each one really counts.
Peel and cut the carrots into ½-inch rounds. On a rimmed baking sheet, toss the carrots with 2 tablespoons of the olive oil and sprinkle generously with salt. Set an oven rack 6 to 8 inches from the heat source and turn on the broiler. Broil the carrots until they brown and soften, turning them over with a spatula every 5 minutes or so; this should take 15—20 minutes.
Meanwhile, bring the stock to a boil. Add the ginger and the sprig of thyme and simmer gently for 15 minutes.
Dice the onion and place in a medium stockpot with the remaining olive oil. Cook the onion over medium heat, stirring frequently, until softened and lightly browned. Season. Add the garlic, and then the carrots.
Remove the ginger and thyme from the stock, and add the stock to the pot with the onions and carrots. Bring to boil and simmer for 5 to 10 minutes, until the carrots are soft enough to purée.
Use an immersion or standard blender to purée the mixture until smooth. If the soup seems too thick, add more stock or water and gently reheat. Add salt and pepper to taste. To serve, ladle into bowls and garnish with chopped fresh thyme.