Using an electric mixer, beat cream cheese in a medium bowl until smooth.
Add 1/4 cup Parmesan and egg; beat to blend.
Beat in sour cream, citrus zest, 4 teaspoons chopped chives, coarse salt and cayenne pepper.
Fold in crabmeat. (This can be made one day ahead. Cover and chill.)
Spray mini muffin pan with nonstick spray.
Toss 1-1/2 cups panko, 3/4 cup Parmesan and 4 Tablespoons chopped chives in a bowl.</span>
Drizzle melted butter over, tossing with a fork until evenly moistened.
Press 1 rounded Tablespoon panko mixture into bottom of each muffin cup (makes a well with your thumb), forming crust.
Spoon 1 generous Tablespoon crab mixture into each cup.
Sprinkle more panko mixture over each.
Bake crab cakes in a 350 degree oven until golden on top and set, about 20 minutes.
Cool in pan 5 minutes.
Gently lift each crab cake out of the pan with a fork onto a serving platter. (Can be made 2 hours ahead)
If serving later, arrange on baking sheet, let stand at room temperature. Rewarm in a 350 degree oven for 5-6 minutes.
Arrange crab cakes on a serving platter; sprinkle with chives.
