Step 1
In a large Dutch oven, stir together the tofu, potatoes, garlic, carrots, onion, mirin, gochujang, soy sauce, gochugaru, ½ teaspoon pepper and 3 cups water. Cover partially and bring to a simmer over medium-high, stirring occasionally. Reduce to medium and cook, stirring, until a skewer inserted into the potatoes and carrots meets no resistance and the cooking liquid is slightly reduced, 35 to 40 minutes.
Step 2
Off heat, stir in the scallions. Taste and season with salt and pepper. Serve drizzled with sesame oil and sprinkled with sesame seeds.