First make the fried tofu. Cut a block of extra firm tofu in half and place on a towel, covering with half the towel. Place a heavy object like a cast iron skillet on top of the tofu for about 1 hour to remove some of the water from the tofu block.
Cut the tofu into cubes and place in a mixing bowl. Drizzle with soy sauce and stir very gently to evenly coat. Sprinkle with cornstarch and stir very gently to coat. Heat olive oil in a skillet on medium high. Fry the tofu cubes, for about 5 - 10 minutes, turning occasionally so that all sides are fried to a golden brown. Remove the tofu and allow it to drain on a paper towel.
Boil 4 cups of water, add the dashi powder and the sliced sweet mini peppers and the white part of chopped scallions. Add the udon noodles and heat for about two minutes.
Transfer the udon noodle soup to two bowls. In a separate small bowl add the miso paste and about 1/2 cup of warm (not boiling) water and stir to combine. Add half the miso mixture to each of the two bowls and stir to combine.
Top the udon miso soup with tofu cubes and garnish with green scallions.