Spiced Beet and Carrot Soup

This soup is tart, quite sweet and satisfying, although it does not contain protein. If you want to increase your protein intake, add more walnuts or serve with a salad of herbs, nuts, and goat's cheese.
Preheat the oven to 425 degrees.Line a baking sheet with parchment paper around the edges. Put the beets and carrots in a bowl. Drizzle with 1 1/2 teaspoons of oil; sprinkle with 1/4 teaspoon of salt. Mix it up. Place the vegetables on the prepared pan. Bake at 425 ° C for 40 minutes or until cooked through, stirring once. Remove from the oven; cool slightly. Cut the beets and carrots into 1-inch-thick slices.Preheat a roasting pan over medium-high heat. Add remaining 1 teaspoon butter; whisk to coat. Add the apple, onion and garam masala to the pan; cook for 1 1/2 minutes. Add beetroot mixture, stock and 2 cups water; bring to a boil. Reduce the heat and simmer for 30 minutes. Remove from heat and let stand for 15 minutes.Put half of the beetroot mixture in a blender and whisk until smooth. Pour the soup into a bowl. Repeat. Add lemon juice. Pour about 1 1/4 cups of soup into each of the 4 bowls; sprinkle each serving with 3 tablespoons of yogurt, 2 tablespoons of walnuts, and about 1 tablespoon of watercress.