day-old rustic white bread., torn into 1-inch pieces (4 cups).Crostini, chips or radicchio leaves.
In a large bowl, blend the mayonnaise with the celery, green pepper, onion, parsley, lemon zest, lemon juice, hot sauce and cayenne.Fold in the crab and season with salt and pepper.
Refrigerate for 1 hour..
In a food processor, pulse the bread until fine crumbs form.Cook, stirring occasionally, until blueberries burst and sauce thickens slightly, about 6 minutes.
Stir in balsamic vinegar.Add sugar to taste, 1/4 teaspoon at a time.
(The amount of sugar will depend on the sweetness of the berries.)Let sauce cool to room temperature, about 1 hour.
