Bring the butter to room temperature so that it is soft enough to blend. Add the butter and wasabi paste to a blender cup or small measuring cup and process with with an immersion blender. Set aside.
Make the wasabi mayo:
Use a fork, or hand whisk to mix the mayonnaise and wasabi paste until uniformly combined. Store in the refrigerator.
Make the coating:
Whisk the breadcrumbs, wasabi powder, peppercorn and sea salt in a shallow dish. Place the egg white and cornstarch in separate bowls and set aside.
Make the scallops:
Heat the water bath to 52ºC/126ºF.
While the water is heating, coat the scallops with the wasabi butter and place 4-6 among 3-4 bags, so that they are not touching. Vacuum seal the bags on delicate setting (if you have it on your vacuum sealer), or stop your machine by pressing the seal button as soon as the bag deflates, without flattening the scallops. If you don't own a vacuum sealer, you can use food and heat safe BPA-free freezer bags and the water immersion method.
Submerge in the heated water and cook for 20 minutes. After cooking, immediately place bags in an ice bath for 15 minutes.
Remove scallops from bag with tongs and place on a sheet of paper towel to soak up excess liquids. Dip, the scallops in the cornstarch and dust off excess before dipping in egg white. Then toss in the panko breadcrumb mixture to coat lightly.
Add a neutral oil, like grape seed, to a skillet and heat to smoking. Place the scallops, flat side down and spaced, in the pan and sear for 1 minute. Flip and repeat. Remove immediately from the pan.
Plate and enjoy:
Sautee a bunch of baby asparagus, shallots and crushed garlic in the same pan. Line the centre of the plates with the sauteed asparagus, top with scallops, microgreens and a light dusting of wasabi powder. Pipe a few dollops of wasabi mayo on the plate, add a lemon wedge and serve!