Pat scallops completely dry with paper towels and season both sides generously with salt and pepper.
Heat olive oil in a large skillet over high heat until shimmering and almost smoking.
Add scallops to the pan without crowding them, and sear without moving for 2-3 minutes until a golden crust forms, then flip and cook another 2 minutes until opaque.
Remove scallops to a plate and reduce heat to medium, then add 2 tablespoons butter and garlic to the pan, cooking for 30 seconds until fragrant.
Add lemon juice and remaining 2 tablespoons butter, stirring until melted and combined.
Return scallops to the pan briefly to coat with sauce, then serve immediately garnished with fresh parsley.