Combine half the oil and half the garlic in a heavy pot over medium-low heat. Cook 1-2 minutes until fragrant. Stir in onion. Increase heat to medium and sauté 6-7 minutes or until softened. Stir in tomatoes, stock, sage and bay leaf. Season with salt and pepper to taste. Simmer 20 minutes. Add beans and simmer 10-15 minutes. While soup is cooking, combine remaining garlic and salt in a mortar and pound to a paste (or use a small bowl and a wooden spoon). Add 1 tablespoon chopped parsley and mash into a paste. Stir in remaining oil, cheese and parsley, and vinegar. Serve soup with a spoonful of sauce.
Serve chilled, if desired.