Kombu, a dried dark seaweed, is available in Asian specialty markets. If you can't find it, add 1/4 teaspoon salt instead. This stew is good served over hot cooked rice.
1 tablespoon vegetable oil
2 cups chopped onion
2 pounds extra-firm tofu, drained and cut into 1-inch cubes
6 cups water
1 cup (1-inch) cubed peeled daikon radish
1 cup (1-inch-thick) slices parsnip
1 cup (1-inch) cubed peeled rutabaga
1 cup (1-inch-thick) slices carrot
1/4 cup low-sodium soy sauce
2 tablespoons mirin (sweet rice wine)
6 dried shiitake mushrooms (about 1/3 ounce)
1 (3-inch square) piece kombu seaweed
6 tablespoons water
1/4 cup cornstarch
2 teaspoons dark sesame oil
1/4 cup chopped green onions
How to Make It
Heat vegetable oil in a Dutch oven over medium heat. Add 2 cups onion, and cook 5 minutes, stirring occasionally. Add tofu; cook 5 minutes or until golden brown, stirring frequently.
Add 6 cups water, daikon, and next 7 ingredients (daikon through kombu); bring to a boil. Cover, reduce heat, and simmer 35 minutes.
Combine 6 tablespoons water and cornstarch, stirring with a whisk. Stir cornstarch mixture into stew; bring to a boil. Cook for 2 minutes, stirring constantly. Discard kombu. Stir in sesame oil; sprinkle with green onions.