In a large mixing bowl, combine your cold cooked rice with the egg yolks, ensuring each grain is well-coated.

Heat 1 tablespoon of neutral or sesame oil in a large skillet over medium heat. Season your salmon fillets with salt and pepper, then place them skin-side down in the hot pan. Cook for about 5 minutes per side, or until the salmon is golden and flakes easily with a fork.

In the same skillet, push the salmon pieces to one side and add another tablespoon of oil. Toss in the chopped cabbage and sauté for 1-2 minutes until tender yet still retains a satisfying crunch.

Add the egg yolk-coated rice mixture along with the chopped green onion to the pan with the sautéed cabbage. Mix everything well and fry the mixture over medium-high heat for about 2-3 minutes.

Pour in the soy sauce and sprinkle the dashi powder over the rice mixture. Add the unsalted butter, tossing everything together over high heat for another 2-3 minutes.

Once ready, transfer to serving plates or a large bowl and garnish with extra chopped green onions. Serve hot.