Crack 3 eggs into a bowl and add ½ tbsp sugar, ½ tbsp sake and ⅛ tsp salt. Stir until the sugar and salt dissolve completely (do not whip it).
Warm a nonstick frying pan over medium heat and oil it lightly. Pour in the eggs. Once they set slightly, stir them into a scramble. When no runny raw egg is left, turn off the heat.
Spread the egg crumbs on a tray or plate. Wipe the pan clean of egg (wash it if any has scorched on). Stir together 1 tbsp Japanese soy sauce (koikuchi shoyu), 1 tbsp oyster sauce, 1 tbsp sake, 1 tbsp mirin and 1 tbsp sugar in a small bowl.
Put the pan back over the heat, oil it, and stir-fry 10 g ginger root for 10-20 seconds. As soon as the ginger is fragrant, add 150 g ground chicken.
As the color turns, speed up your stirring a little. Cook until the chicken is in small, separate crumbs and no pink shows.
Pour in the soboro seasonings and boil over high heat. While the pan is still wet with plenty of liquid, wash the bowl you used for the eggs. Near the end, keep stirring along the bottom of the pan, and take it off the heat once the liquid has cooked off completely.
Bring a generous 1 L of water to a boil in a pot. While you wait, fill a bowl with ice and water. Make a cross-shaped cut in the root end of 120 g Oriental spinach, then wash away the grit under running water.
When the water boils, add 2 tsp salt. Put the spinach in roots first and boil for 30 seconds, then sink the leaves and boil 15-30 seconds longer (do not cover the pot).
Transfer the spinach right away to the ice water. After 30 seconds, when it feels cold, take it out. Drain in a colander, wring firmly with both hands and chop into 3-4 cm pieces.
Mix 1 tsp Japanese soy sauce (koikuchi shoyu), 1 tsp toasted sesame oil, 1 tsp ground sesame seeds and 1 g bonito flakes (katsuobushi) in a bowl. Add the spinach and toss well.
Rewarm the soboro gently. Divide 2 portions cooked Japanese short-grain rice among the bowls and level the surface with the back of a spoon.
Picture the rice in thirds. Spoon the egg crumbs onto one third and the soboro onto another, each in a single mound, then finish the last third with the sesame spinach. Top each bowl with 1 tbsp red pickled ginger (benishoga) if you like. Enjoy!
Notes
Break up the white before cooking: Strands of white left in the eggs cook into white specks and cloud the yellow. Keep mixing until no clear strands remain.Hold off on seasoning while it reduces: Salt and sweetness both concentrate as the liquid boils off. Soboro that tastes right while the pan is wet ends up too strong once it is dry. Taste only when the liquid is almost gone.If the soboro comes out dry: Add a splash of mirin or water, cover and set over low heat. Turn off the heat as soon as it is warm.Squeeze the spinach completely dry: Leftover water pools at the bottom of the bowl, turns the rice soggy and thins the dressing. Made ahead, the spinach weeps even more water.Serve on warm rice: Soboro fat firms up on cold rice. Fill the bowls while the rice and the soboro are both warm.Mix as you eat: Keep the 3 toppings in their own sections, and scoop a little of each onto the rice with every bite.