Toast the bread slices if desired, then spread Santina Mayonnaise evenly on one side of each slice. Layer lettuce leaves on one slice, followed by turkey, cheese, tomato, and pickles. Place the second slice of bread on top, mayonnaise side down.
Shrimp
1- Using kitchen shears and working one at a time, cut along the length of the backs of shrimp, cutting through shells and just deep enough into flesh to expose veins; remove veins.
2- Bring a large saucepan of salted water to a boil and add ¼ cup Old Bay seasoning. Squeeze lemon juice into water and add lemon halves to saucepan; return water to a boil. Add shrimp, reduce heat, and simmer until cooked through, about 3 minutes. Transfer to a bowl of ice water and let cool. Drain and pat dry.
3- Just before serving, whisk oil and remaining 1 Tbsp. Old Bay in a medium bowl. Add shrimp and parsley and toss to coat.
4- DO AHEAD: Shrimp can be cooked 1 day ahead. Cover and chill.
Mustard-Lime Dipping Sauce
5- Whisk mayonnaise, brown mustard, lime juice, honey, brown sugar, mustard powder in a medium bowl; season with hot sauce and salt. Serve shrimp with dipping sauce and lime wedges.
1- Cook shrimp in a pot of boiling salted water until cooked through, about 2 minutes. Drain; rinse with cold water until cool. Pat dry and chop into bite-size pieces.
2- Whisk together celery, scallions, mayonnaise, dill, lemon juice, horseradish, vinegar, and paprika; season with salt and pepper. Fold in shrimp.
3- Meanwhile, heat broiler. Toast buns on rimmed baking sheet until golden brown, about 3 minutes. Spread butter on each toasted bun and fill with shrimp salad.
Heat broiler. Toss shallot, leek, and scallions with olive oil; season with salt. Broil, tossing once, until charred, 10–15 minutes. Let cool. Mix with garlic, mayonnaise, sour cream, lemon juice, and thyme. Thin with buttermilk; season with salt and pepper. Serve topped with thyme.
1- Purée anchovies, garlic, oil, lemon juice, mayonnaise, mustard, and 2 Tbsp. Parmesan in a blender until smooth. Season dressing with salt and pepper. (Or, finely chop anchovies and garlic and whisk together dressing in a medium bowl.)
2- Arrange tomatoes on a large plate; drizzle dressing over. Top with basil and shaved Parmesan; season generously with pepper.