Preheat oven to 400 and line a baking sheet with foil. Toss vegetables, garlic, oil, thyme, ½ teaspoon salt and ¼ teaspoon pepper together and place on baking sheet in an even layer. Roast until vegetables are tender, about 40 minutes. Remove garlic peels.Combine vegetables with chicken broth and in blender and process until smooth (you may have to work in batches).Pour vegetable puree into a saucepan, add paprika and heat over medium heat, thinning with extra chicken broth as needed until it is hot and the consistency you like. Taste and add salt and pepper as needed.Ladle into soup bowls, garnish with sour cream if you like and serve.