Fill a large stock pot halfway with water.

Add chopped onions, garlic, and celery to the water.

Add cayenne pepper (optional) to the water.

Bring the water to a boil.

Rinse the shrimp and crab.

Set the shrimp and crab aside.

Wash the red potatoes.

If the potatoes are small, add them whole to the boiling water.

Otherwise, slice the potatoes in half and add to the boiling water.

Boil the potatoes for 10 minutes.

Slice the ears of corn into two or three chunks.

Add the corn to the potatoes in the boiling water.

Boil the corn and potatoes for 10 minutes.

Add the shrimp, crawfish, and crab boil seasoning bag to the boiling water.

Slice the sausage into chunks.

Add the sausage to the water.

Reduce the heat.

Cook for 6 minutes.

Add the crab legs to the pot.

Cover and cook for 10 minutes, ensuring they are heated through.

Adjust the cooking time based on the size of the crab legs.

Add the shrimp to the pot.

Cover and cook until the shrimp turn pink and separate from their shells.

Slice the French bread.

Butter the bread slices.

Broil the bread until lightly browned.

Serve the low country boil immediately.

Optionally, remove the pot from direct heat and let the food absorb more of the flavors from the water before serving.

Serve with hot sauce, lemons, and butter.