3/4 lb. lg. shrimp, shelled and deveined
3/4 lb. sea scallops
3 tbsp. fresh lemon juice
2 tsp. Dijon-style mustard
1/2 c. safflower or other light vegetable oil
3 tbsp. light olive oil
1/2 tsp. salt
1/4 tsp. freshly ground pepper
2 tbsp. chopped fresh dill or basil
2 or 3 heads Bibb lettuce

Bring a large saucepan of water to a boil over high heat. Add the shrimp and scallops. When the water returns to a boil, drain the seafood into a colander. Rinse under cold running water until cool; drain well.

Slice the shrimp in half lengthwise. Cut the scallops horizontally in to 2 to 3 rounds. Cover the seafood and refrigerate. (The seafood can be prepared up to a day ahead.)

In a large bowl, blend together the lemon juice and mustard. Gradually whisk in the safflower and olive oils. Season with the salt and pepper and stir in the chopped herbs.

To serve, arrange the lettuce leaves on 6 serving plates. Whisk the vinaigrette to mix, add the chilled seafood and toss to coat. Arrange the dressed seafood on top of the lettuce.