Prepare Rice: Soak the rice in cold water for 30 minutes.
Prepare Ingredients: Smash and finely chop garlic. Thinly slice green onions, separating whites from greens.
Season Water: Mix soy sauce, mirin, dashida, and water in a container.
Cook Ground Beef: Heat oil in a pot over medium heat. Add ground beef, season with salt, and cook until golden brown. Add garlic and white parts of green onions, sautéing for 3-4 minutes.
Cook Rice: Remove beef, leaving oil in the pot. Add drained rice, stir-frying for 1 minute. Add seasoned water, bring to a boil, then simmer covered with beef on top for 15 minutes. Let it sit covered off the heat for an additional 10 minutes.
Finish and Serve: Sprinkle green onions over rice, mix, and optionally add raw egg yolk, butter, or toasted sesame oil for extra flavor.