1.Crack the eggs in a bowl. Add dashi powder and white pepper. Beat well. Then stir in 3 tablespoons tobiko and 1 tablespoon green onion and combine.
2.Heat oil and butter on medium low heat. Tilt the pan to ensure the surface is evenly greased. Beat the egg mixture one last time to ensure the roe is evenly distributed, then pour the egg into the pan. Fold the egg by pulling edges with a spatula to draw the egg from various sides to the center, letting uncooked egg flow underneath. Do so until the egg is just set with some raw egg still on top.
3.Cut the egg to chunks with the spatula and fry quickly until there is no more raw egg. Take the omelette off the heat immediately.
4.To serve, dish the omelette out to a plate, garnish with remaining tobiko and green onions.