In an 8-quart pot, bring Zatarain's Crab Boil, water and potatoes to boil on high heat.
Add onion and lemon halves.
Cook 13 minutes.
Add corn and sausage.
Continue to cook 7 minutes.
Remove from heat.
Let sit for 10 minutes.
Drain and dump contents in the center of a paper-covered picnic table.
Sprinkle additional Zatarain's Crab Boil seasoning over the top for flavor.