Sprinkle breadcrumbs over crabmeat in a medium bowl.
Stir together mayonnaise and next 7 ingredients in a small bowl; pour over crabmeat mixture, and toss gently. Shape mixture into 5 (3-inch) patties. (Mixture will be very soft.) Cover and chill at least 1 1/2 hours.
Brush crab cakes with 2 tablespoons clarified butter. Sprinkle evenly with Blackening Spice. Cook crab cakes in 1/4 cup clarified butter in a hot cast-iron skillet over medium-high heat 2 to 3 minutes on each side. Serve with Reddened Butter Sauce.
Note: To make clarified butter, melt 1/2 cup butter over low heat. (Fat rises to the top, and milk solids sink to the bottom.) Skim off white froth that appears on top; strain off clear, yellow butter, keeping back the sediment.