How to Make It
Bring 6 cups water to a boil in a large saucepan. Fill a large bowl with ice water.
Add shrimp to boiling water; cook just until shrimp turn pink, about 3 minutes. Drain well, and immediately place shrimp in ice water bath. Drain again, and pat shrimp dry with clean kitchen towels.
Stir together sour cream, olive oil, buttermilk, vinegar, salt, and pepper in a bowl; stir in crumbled blue cheese.
Layer romaine, tomatoes, red cabbage, cucumbers, carrots, and avocado in a 4-quart trifle dish. Spoon dressing over top. Arrange cooked shrimp in the center; place eggs and olives around shrimp. Sprinkle with parsley.