In a medium saucepan over high heat, add 2 cups of the water and black-eyed peas. Bring to a boil for 2 minutes, cover, remove from heat and let stand for 1 hour.
Drain the water, leaving the peas in the saucepan. Add the remaining 1 cup of water, bouillon granules, tomatoes, onion, celery, garlic, mustard, ginger, cayenne pepper and bay leaf. Stir together and bring to a boil. Cover, reduce heat and simmer slowly for 2 hours, stirring occasionally. Add water as necessary to keep the peas covered with liquid.
Remove the bay leaf, pour into a serving bowl and garnish with parsley. Serve immediately.