Notes: This is one component of Oahu Bouillabaisse. If making ahead, cover potatoes tightly and keep warm in a 250° oven up to 30 minutes; stir in crab just before serving.
1. In a 5- to 6-quart pan, bring 2 1/2 quarts water to a boil.
2. Meanwhile, peel potatoes and cut into 1 1/2-inch chunks. Add potatoes to boiling water, cover, and simmer until tender when pierced, about 20 minutes; drain.
3. Mash potatoes, adding aioli and enough broth to make potatoes creamy.
4. Stir in crab. Add salt and pepper to taste. Use in bouillabaisse or serve.