Preheat oven to 425°F and line a baking sheet with foil.
Rinse crabmeat under cold water. Take small handfuls of the crabmeat and squeeze dry gently, using your fingers to remove any pieces of shell that might remain in the meat. Set crabmeat aside in a small bowl.
In a large bowl, combine mayonnaise, both mustards, Worcestershire sauce, lemon juice, egg yolk, Old Bay seasoning, salt, and pepper. Stir to combine well.
Gently stir in ½ cup panko breadcrumbs, then fold in the crabmeat, being careful not to break up the lumps too much. Chill mixture for 20 minutes.
Use a small cookie scoop to portion out the mixture, then wet your hands and roll each scoop into a ball.
Put the remaining ½ cup panko in a shallow bowl and roll each crab ball to coat. Arrange the crab balls on the prepared sheet pan.
Melt butter in a small bowl. Paint crab balls with the melted butter.
Bake for 15 minutes, then broil for 2 minutes to brown the tops, watching closely so they don’t burn.
Serve with lemon wedges and chopped parsley or chives.
Notes
Make ahead: mix filling and refrigerate up to 24 hours before rolling and baking.Freezer: freeze raw or baked, up to 3 months.Reheat: 400°F oven for 10 minutes, or air fryer at 375°F for 5 minutes.Expert Tips: Painting the crab balls with melted butter before they go in the oven is what gives you that deep golden color and crisp panko coating, without ever touching a deep fryer. You can paint on a little more after broiling too if you want extra shine.Don’t skip the chill time. That 20 minutes firms up the mixture so the crab balls hold their shape instead of spreading out.