To hard-boil eggs, bring 1/2- to 1-inch of water to the boil in a large saucepan on high heat. Carefully add eggs into boiling water using a large spoon or tongs. Cover and cook for 12 minutes for large eggs (adjust time up or down by 1 minute for each size larger or smaller). Drain water immediately. Rapidly cool eggs by running them under cold water or placing them in a bowl of ice water. . Peel eggs and refrigerate until completely cool.
Slice eggs in half lengthwise. Remove yolks and place in a small bowl. Mash yolks with a fork or potato masher. Stir in mayonnaise, mustard and OLD BAY until well combined. Gently stir in 1/2 of the crab meat.
Spoon or pipe yolk mixture into egg white halves. Top evenly with remaining crab meat, parsley and an additional sprinkle of OLD BAY, if desired. Refrigerate for 1 hour or until ready to serve.