Tuna and Shells Dijon

1 can, 12 ounces, tuna, drained and flaked
1 cup diced red, yellow or green bell pepper
1/3 cup chopped green onions
2 teaspoons mustard seed
2 tablespoons butter or margarine
2 tablespoons all purpose flour
2 1/2 cups low fat milk
3 to 4 tablespoons Dijon mustard
1 teaspoon grated lemon peel
1/2 teaspoon salt
1/4 teaspoon pepper
1 package, 7 ounces, medium shells, cooked and drained
2 tablespoons chopped parsley

In a medium saucepan, saute bell pepper, onions and mustard seed in butter for 3 minutes. Sprinkle flour over mixture, stirring until blended. Add milk all at once. Cook and stir until mixture thickens and bubbles. Stir in mustard, lemon peel, salt and pepper until blended.

Fold in tuna and shells; cook for 2 minutes more to heat through.

Serve in 4 to 6 individual casseroles or ramekins, sprinkled with parsley.