Heat the olive oil over medium heat in a large stockpot or dutch oven. Add the onion, carrots, and celery. Cook, stirring occasionally, for 6–7 minutes as the vegetables soften up and let out some juices. Add the garlic, Old Bay seasoning, and ground mustard. Stir to combine and cook 1 minute.

Add all of the remaining ingredients, except for the crab and optional garnishes. Bring to a boil. Add the crab. Cover and simmer for 30 minutes. Remove bay leaves.

Serve soup warm with a garnish of lemon pepper seasoning and fresh parsley, if desired.

Keep leftovers in a large covered container in the refrigerator for up to a week. To reheat, simply pour into a pot over medium heat and cook until warm. Feel free to add more broth to the leftovers as it cooks if it is too thick—I always do. (It thickens in the refrigerator as the veggies and crab soak up the liquid.)