In a large pot, over medium to medium-low heat, melt butter. Add onion, carrot, celery and green pepper. Gently sauté over medium low heat for 20 minutes, stirring occasionally.
Add boiling water, soup base, garlic powder, bay leaf and Worcestershire sauce, tomatoes with juice, elbows and lentils. Stir and slowly simmer for an hour with lid ajar, stirring occasionally until lentils are soft. Add sugar and milled flax seed. Remove the bay leaf. Stir and serve.