Check crab meat — pick out any shell pieces.
Mix wet ingredients — in a bowl, stir together egg, mayo, mustard, Old Bay, lemon juice, and parsley.
Add crab and breadcrumbs — fold in crab meat gently, then add breadcrumbs. Mix lightly so the crab stays chunky.
Shape — form into 4–6 patties, about ½–1 inch thick.
Chill — place patties in the fridge for 30 minutes to help them hold together.
Cook — heat oil or butter in a skillet over medium heat. Fry crabcakes for 3–4 minutes per side until golden and hot inside.
Serve — plate with lemon wedges and your favorite sauce.