Add the broth and water and bring to a boil.

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.

Spread the breadcrumbs on a rimmed baking sheet and toast for about 8 minutes, until crisp..

In a large skillet, cook the butter over moderate heat until the milk solids turn dark golden, about 4 minutes.Pour processed watermelon through a fine wire-mesh strainer into a medium bowl to yield 1 1/2 cups watermelon juice (enough for 8 cocktails).

Chill juice until ready to make cocktails.. Salt half the rim of a chilled coupe glass.Add white rum, lime juice, agave nectar, and 3 tablespoons watermelon juice to a cocktail shaker filled three- fourths of the way with ice.

Cover and shake vigorously until well combined, about 10 seconds.Strain into coupe glass.