Instruction

1. Preheat oven to 350°F. Place onion, carrot, and scallions on a small rimmed baking sheet. Bake the vegetables, turning once, until softened and lightly browned, about 40 minutes,
2. Halfway through baking time, bring sake to a boil in a large saucepan over medium-high. Reduce heat to medium-low; simmer, undisturbed, until the smell of alcohol disappears, about 5 minutes.
3. Add the baked vegetables, mirin, soy sauce, sugar, garlic, and ginger to the sake in the saucepan. Bring the mixture to a simmer over medium-high, then reduce the heat to maintain a simmer. Cook, stirring occasionally, until the sauce is thickened to a syrup consistency and coats the back of a spoon, 45 minutes to 1 hour. Pour the sauce through a fine mesh strainer placed over a small heatproof bowl; discard solids. Set sauce aside.
4. Preheat oven to broil with rack 5 inches from heat source or preheat a grill over medium-high. Place unagi halves on a clean cutting board. Carefully insert bamboo skewers crosswise through unagi halves, spacing 1-inch apart. Trim off excess skewers. Pour water into a wok or large skillet to a depth of 2 inches; bring to a boil over medium-high. Place skewered eel on racks of a bamboo steamer. Cover with lid, and place over wok. Cook over medium-high, without opening lid, until unagi is tender, 5 to 10 minutes depending if your unagi is already cooked or raw. Transfer steamed unagi to a large rimmed baking sheet lined with foil. Remove skewers, and pat dry. Brush each unagi piece generously with about 1 teaspoon of the prepared sauce.
5. Broil or grill the unagi until golden, about 2 minutes. Baste unagi again, and broil or grill until deep golden brown and starting to caramelize, 1 minute more.
6. For each serving, place cooked rice in a bowl, and place 2 unagi pieces on top of rice; drizzle with 1 teaspoon prepared sauce. Top with ginger and sansho pepper.