Quarter the onion. Chop the corn and sausage into roughly equal-sized pieces.

Fill a large pot three-quarters full with water. Add the onion, lemon and Old Bay seasoning, and bring to a boil.

Once boiling, add the potatoes. Cook for 15 to 20 minutes, or until fork-tender.

Add the corn and sausage and cook for another 5 to 7 minutes.

Add the shrimp and cook for no longer than 2 to 3 minutes.

Use a spider strainer to remove all ingredients from the pot, then season with additional Old Bay to taste. Serve immediately with cocktail sauce and crusty bread.

Whisk all ingredients together in a small bowl until smooth and well combined. Taste and adjust horseradish, lemon juice or seasoning as desired. Chill until ready to serve.