For oysters: Preheat oven to high broil. Use an oyster knife to remove top of the oyster. The top is flat, not cup-shaped. Place oysters on a sheet tray or small pan lined with salt, and top each with 1 tablespoon of XO-Egg sauce. Broil on high for 4 minutes or until brown. Remove from oven and garnish each with scallion and dash of Korean powder. Sprinkle coarse salt over serving plate to stabilize oyster shells, if desired.
For XO-egg sauce:
Blend first four ingredients in a blender. Slowly add oil and egg yolks.
For XO sauce:
Put each ingredient into food processor separately, and process until very fine. Place all processed ingredients in a pan and cook over low heat, until browned.