Peel and chop the onion into 6 equal pieces.
Fill a large pot about halfway with water, add 2 tbsp Zatarain's Crawfish, Shrimp & Crab Boil, 1 tbsp Old Bay Seasoning, the chopped onion, squeeze the juice from the limes into pot and place the peels in the water, then bring to a boil.
If using frozen shrimp, follow the instructions on the packaging to thaw (if the shrimp isn't already thawed).
Slice the baby potatoes in half and slice the sausage into pieces that are approximately 1 inch wide.
Once the water is boiling, add the baby potatoes. Reduce heat to medium-high and allow to boil for 10-12 minutes. Stir occasionally.
Add the sausage and allow to cook for 5 minutes. Stir occasionally.
Add the thawed shrimp to the pot and allow to cook for 3 minutes. Stir occasionally,
Turn off heat, allow to cool and place equal amounts in meal prep containers.