Clean the crawfish by rinsing thoroughly under cold water, removing any dead ones. Optionally purge in saltwater briefly.

Fill a large pot with about 6 quarts of water. Add Cajun seasoning, bay leaves, smashed garlic, quartered onions, salt, and juice of one lemon half. Bring to a rolling boil over high heat.

Add red potatoes and corn pieces to the boiling water. Boil until potatoes are just tender, about 10-15 minutes.

Add sliced andouille sausage and live crawfish to the pot. Stir gently, cover, and boil for 5-7 minutes until crawfish turn bright red and float to the top.

Turn off heat and keep the pot covered. Let everything steep in the spicy broth for 15-20 minutes to absorb flavors.

Using a strainer basket or slotted spoon, lift crawfish, veggies, and sausage out of the pot. Transfer to a large serving bowl or newspaper-lined table.

Drizzle melted butter over the boil and toss lightly to coat.

Garnish with chopped fresh parsley if desired and serve with lemon wedges.