7 cups water
1 tablespoon instant dashi
1/2 cup soy sauce
1 tablespoon sugar
1/2 pound dried soba* (buckwheat noodles)
2 carrots, sliced thin
1/2 pound spinach, coarse stems discarded and the leaves washed well, spun dry, and cut crosswise into 1 1/2-inch-wide strips
8 to 10 ounces firm tofu (preferably silken), cut into 1/2-inch cubes
3 to 4 tablespoons miso* (fermented bean paste), or to taste, if desired
2 scallions, minced
*available at Japanese markets.