Clean the scallops by removing the loose flap or "foot" on the side. (It will turn tough once cooked.) Then place the scallops on a paper towel to dry. Pat the tops with another paper towel.
Heat a large skillet to medium-high heat. Drizzle a scant amount of oil in the skillet and brush it over the surface of the pan. You just want the pan to be lightly coated, not pooling with oil.
Once the pan is smoking-hot, place the scallops in the skillet flat-side-down. Sprinkle with salt and pepper and allow them to sear for 1-2 minutes. You'll know the scallops are ready to flip when they pull away from the skillet easily, and are caramelized. If they hold tight to the skillet, give them a little longer.
Flip the scallops, salt and pepper again, and sear for 1 minute. Then add the butter and garlic to the skillet. Sear another minute, turn off the heat. Add the lemon juice, one pinch of lemon zest, and the parsley. Toss to coat and serve immediately.