White Soondubu Jjigae (Mild Tofu Stew)

Name: White Soondubu Jjigae (Mild Tofu Stew)
Cook time: 40 min
Total time: 40 min
Cuisine: Korean
Ingredients: 1 (6-inch) square dried kelp (also labeled as dashima or kombu); 8 ounces Korean radish or daikon, peeled and sliced ¼-inch thick, then cut into 1-inch pieces (2 cups); 3 dried shiitake mushrooms; 2 tablespoons neutral oil, such as safflower or canola; 4 scallions, thinly sliced; Salt and black pepper; 1 tablespoon minced garlic; 2 teaspoons toasted sesame seeds; 1 teaspoon minced ginger; 1 large zucchini (8 ounces), halved lengthwise and sliced into ¼-inch-thick half-moons (2 cups); 1 tablespoon low-sodium soy sauce; 1 1/2 pounds silken tofu, broken into large pieces with a spoon; 1/4 teaspoon toasted sesame oil; Steamed rice, for serving