Steam your vegetables if you have not already done so and set aside.Heat oil in a large skillet on medium-high heat. When the oil is hot, add temper cubes and 1 tablespoon of tamari and stir to combine.
Reduce heat to medium. Brown each side for 4-5 minutes. Set aside on a plate.Meanwhile, make sauce by mixing the remaining tamari, sesame oil, mirin, ginger, garlic and red pepper flakes (if using) in a small bowl.
Heat the noodles on medium-low heat in the skillet. Add the sauce and stir to combine.Add the nut butter and stir to combine. Place temper back in skillet and mix with the noodles so that everything is covered in the sauce.
Turn off heat to serve, divide steamed vegetable mixture among 4 bowls. Top with about 1 ½ cups temper and noodles.
Sprinkle sesame seeds on top and garnish with cilantro and scallions. Enjoy hot or cold.Store leftovers in refrigerator for up to 5 days.