Preheat the oven to 375 degrees.Trim and discard the tip from each head of garlic. Place the heads on a plate and microwave on high power for 5 minutes. Carefully pop the individual cloves out of their skins and place the peeled cloves in a small bowl. Drizzle with 1 tablespoon of the oil and stir to coat. Transfer the cloves to a baking sheet, making sure that the cloves do not touch. Bake the cloves in the preheated oven just until golden and softened, 10 to 15 minutes. Do not let the cloves turn brown. Set aside to cool.Meanwhile, in a stockpot, bring the water, onion, carrots, potatoes and salt to a boil and cook until the carrots and potatoes are soft, 15 minutes.Add the roasted garlic and its oil to the stockpot. Add the anchovies and cook, stirring constantly, until the anchovies dissolve. Remove the pan from the heat; set aside to cool slightly.While the soup is still in the pot, use a potato masher to mash the mixture. (Do not use a food processor or blender; the finished soup should have plenty of texture.) Add the pepper and remaining 2 tablespoons olive oil. Taste and adjust seasonings accordingly.Per serving (based on 6): 187 calories, 4 gm protein, 28 gm carbohydrates, 7 gm fat, 3 mg cholesterol, 1 gm saturated fat, 524 mg sodium, 3 gm dietary fiber.