Pour water in a four-gallon stockpot and fill it up till ⅔ full with water. Boil it on a high heat flame. Blend all of the Cajun seasoning ingredients in a small-sized bowl and keep it aside. Add garlic, potatoes, salt, onion, six lemon halves and half of the seasoning blend and add it to the stockpot. Cover it up and lightly boil it. Decrease the heat flame to medium heat; keep cooking for 10 minutes.

Pour corn, sausage and peppers into it and lightly boil it. Cook the dish for extra 5 minutes. Pour crawfish into it, and come to boil. Pour mussels with shrimps and cook the dish for extra 5-8 minutes; wait until all the mussels open up, and shrimps change their shade. Take out from heat and drain well.

Pour butter and other remaining seasoning mix and toss it well. Cover up the stockpot. Allow it to steam for some time. Serve the dish along with some salad or lemon wedges.