Remove the tough side muscle from the scallops if present.
Pat scallops thoroughly dry with paper towels to ensure a proper sear.
Season scallops with salt and pepper immediately before cooking.
Heat oil in a heavy skillet over high heat until it begins to shimmer and smoke slightly.
Place scallops in the pan, leaving space between each piece.
Sear for 2 minutes without moving until a golden-brown crust develops.
Flip scallops and sear the second side for 1 to 2 minutes until opaque throughout.
Transfer scallops to a warm plate.
Reduce heat to medium and sauté shallots and garlic in the same pan for 1 minute.
Deglaze the pan with white wine and lemon juice, reducing the liquid by half.
Whisk in the chilled butter cubes one at a time to form a smooth emulsion.
Stir in fresh parsley and spoon the sauce over the seared scallops.