Preparation Heat 2 tablespoons oil in heavy large skillet over medium-high heat. Sprinkle shrimp with salt and pepper; add shrimp to skillet and sauté until just opaque in center, about 3 minutes. Transfer to plate. Whisk next 5 ingredients in large bowl. Whisk in 8 tablespoons oil; season with salt and pepper. Mix in shrimp and accumulated juices, capers and green onions. Cool slightly, then cover and refrigerate at least 3 hours and up to 1 day. Arrange butter lettuce leaves on 8 plates. Top with shrimp, dividing equally. Drizzle with more marinade, if desired. Garnish with lemon rounds and fresh dill sprigs, if desired.
Preparation Heat 2 tablespoons oil in heavy large skillet over medium-high heat. Sprinkle shrimp with salt and pepper; add shrimp to skillet and sauté until just opaque in center, about 3 minutes. Transfer to plate. Whisk next 5 ingredients in large bowl. Whisk in 8 tablespoons oil; season with salt and pepper. Mix in shrimp and accumulated juices, capers and green onions. Cool slightly, then cover and refrigerate at least 3 hours and up to 1 day. Arrange butter lettuce leaves on 8 plates. Top with shrimp, dividing equally. Drizzle with more marinade, if desired. Garnish with lemon rounds and fresh dill sprigs, if desired.