Season the boiling water

• Fill a large stockpot with water and bring to a boil.
• Add the lemon, onion, garlic, bay leaves, Cajun seasoning, Old Bay and salt.

Boil the potatoes and corn

• Add the potatoes and cook until almost tender.
• Add the corn and continue cooking.

Add the sausage

• Add the sliced sausage to the pot and cook until heated through.

Cook the shrimp

• Add the shrimp and cook until pink and opaque.

Drain and serve

• Drain everything in a colander.
• Toss with melted butter and sprinkle with parsley.