Sauté the onion in the oil in a medium-size pot until softened but not browned, about 3 minutes. Add the garlic and curry; sauté for 1 minute. Stir in the water and the instant bouillon granules.
Meanwhile, wash and pick over peas. Add to pot along with carrot, celery, cloves and pepper. Bring to boiling. Lower heat; cover and simmer 1 hour.
Cool slightly. Working in batches, spoon soup into a blender or food processor. Whirl until a smooth puree. Return puree to pot. Stir in lemon juice and salt. Heat to serving temperature.
Ladle into soup bowls and garnish with dollop of yogurt if you wish and Pumpernickel Croutons.
Cut pumpernickel bread into matchstick pieces. Place the bread in a large nonstick skillet. Sprinkle with oil. Heat the skillet over medium heat, stirring often, until the bread is crisped on all sides. Remove skillet from heat.