Preparation Rinse spinach and drain lightly. With water still clinging to leaves, cook in 3 batches in an 8-quart pot over moderately high heat, covered, turning occasionally with tongs, until wilted and bright green, 2 to 3 minutes per batch. Transfer as cooked to a colander, then rinse under cold water until cool and drain well. Squeeze small handfuls of spinach to remove as much moisture as possible, then in 3 batches wrap spinach in several layers of paper towels and squeeze to remove even more moisture. Coarsely chop spinach. On a 16-inch sheet of plastic wrap, form half of spinach into a 13 1/2- by 1 1/2-inch log. Repeat with remaining spinach on another sheet of plastic wrap. Use plastic wrap and your hands to roll, compact, and smooth sides of logs. Remove and discard plastic wrap. With a sharp knife, cut each spinach log crosswise into 9 (1 1/2-inch) pieces (18 total), then arrange, cut sides up, on a platter, reshaping and smoothing mounds with your fingers. Finely grind 2 teaspoons sesame seeds in a blender, then add peanut oil, vinegar, mirin, shoyu, sesame oil, and salt and blend until combined well. Spoon 1 teaspoon dressing over each spinach mound, stirring dressing occasionally (it will separate as it stands), and sprinkle mounds with remaining 4 teaspoons sesame seeds. Cooks' notes:· Spinach can be cooked 1 day ahead, then cooled, drained, and kept in a bowl, covered and chilled. Bring to room temperature before proceeding, about 1 hour. · Dressing can be made 1 day ahead and chilled, covered. Bring to room temperature, about 1 hour, and whisk to combine before using.
Preparation Rinse spinach and drain lightly. With water still clinging to leaves, cook in 3 batches in an 8-quart pot over moderately high heat, covered, turning occasionally with tongs, until wilted and bright green, 2 to 3 minutes per batch. Transfer as cooked to a colander, then rinse under cold water until cool and drain well. Squeeze small handfuls of spinach to remove as much moisture as possible, then in 3 batches wrap spinach in several layers of paper towels and squeeze to remove even more moisture. Coarsely chop spinach. On a 16-inch sheet of plastic wrap, form half of spinach into a 13 1/2- by 1 1/2-inch log. Repeat with remaining spinach on another sheet of plastic wrap. Use plastic wrap and your hands to roll, compact, and smooth sides of logs. Remove and discard plastic wrap. With a sharp knife, cut each spinach log crosswise into 9 (1 1/2-inch) pieces (18 total), then arrange, cut sides up, on a platter, reshaping and smoothing mounds with your fingers. Finely grind 2 teaspoons sesame seeds in a blender, then add peanut oil, vinegar, mirin, shoyu, sesame oil, and salt and blend until combined well. Spoon 1 teaspoon dressing over each spinach mound, stirring dressing occasionally (it will separate as it stands), and sprinkle mounds with remaining 4 teaspoons sesame seeds. Cooks' notes:· Spinach can be cooked 1 day ahead, then cooled, drained, and kept in a bowl, covered and chilled. Bring to room temperature before proceeding, about 1 hour. · Dressing can be made 1 day ahead and chilled, covered. Bring to room temperature, about 1 hour, and whisk to combine before using.