For the Shrimp
To steam the shrimp, wrap 6 shrimp in parchment paper, folding the ends over to make a package. Continue with the rest of the shrimp--6 to a packet. Place on a steamer over boiling water. Cover and steam until just cooked through. The shrimp will take about 5 to 6 minutes, depending on size. Remove from the parchment paper while still warm--a messy job. Discard the juices and let shrimp cool. For the Shrimp with Mayonnaise
Spoon the mayonnaise into a bowl large enough to hold the shrimp. Add the lemon juice and chives, and mix. Season with salt and pepper and toss in the shrimp.
For the Tuna
Enza's version is to use tuna instead of shrimp. You can use canned tuna in olive oil, adjusting the mayonnaise accordingly.
For the Shrimp with Vinaigrette Spoon the mustard into a small bowl. Whisk in the white wine vinegar and the lemon juice. Continue whisking while slowly dribbling in the oil until the mixture emulsifies. Add the capers, and salt and pepper to taste. Pour half the vinaigrette with most of the capers over the shrimp and toss. Add more vinaigrette if needed. Reserve any extra vinaigrette to toss over lettuce or to drizzle over grilled white fish.
For the Egg Salad
Spoon the mayonnaise into a bowl large enough to contain the chopped hard-boiled eggs (see Cook's Tip). Add the minced dill and toss the eggs in the dressing. Season with salt and pepper. Extra egg salad can be kept refrigerated for 2 days.
Assembly
Core the tomatoes with a melon baller. Sprinkle with salt and place cut-side down on paper towels to drain for 20 minutes. Pat the insides of the tomatoes dry with paper towel and fill, heaping generously with any of the three mixtures. Top each egg-stuffed tomato with a sprig of dill and an olive. Top the shrimp-stuffed tomatoes with basil and serve on a bed of lettuce.
Cook's Tips
1. Prepare hard-boiled eggs the way restaurant kitchens do: rub the peeled, whole eggs through the large-hole side of a grater.
2. When cutting basil, roll the leaves up like a jellyroll for easy cutting. Cut basil at the last moment as the cutting can bruise and darken the leaves.