Combine the 1 tsp (0. 17 oz / 5g) wasabi paste, 1 tsp (0. 17 fl oz / 5ml) water, and 2 tbsp (1 oz / 28g) mayonnaise in a small bowl, mixing well until completely smooth and incorporated.
Heat the 1 tbsp (0. 5 oz / 14g) butter in a large skillet over medium-high heat until it begins to brown and smell nutty.
Add the seasoned scallops to the hot skillet, ensuring they do not touch, and sear for exactly 1. 5 minutes on each side until a deeply caramelized, golden-brown crust forms.
Remove the skillet from the heat and immediately transfer the scallops to two serving plates, allocating 4 scallops per plate.
Top each freshly seared scallop with a generous dollop of the prepared wasabi mayo mixture.
Dry is Key to a Good Sear: Scallops hold a lot of moisture. To get that restaurant-quality, golden-brown crust, you must pat them completely dry with paper towels before seasoning. If they are wet, they will steam instead of sear.
Do Not Disturb: Once you place the scallops in the pan, leave them alone. Resist the urge to peek or move them around.
Letting them sit undisturbed for the full 1. 5 minutes ensures the Maillard reaction occurs, creating that beautiful caramelization.