Prepare the edamame. Add sesame oil to a nonstick pan over medium heat. Add the edamame and sauté until it turns slightly golden brown. Then add sesame seeds, red chili flakes, pepper, maple syrup, and soy sauce. Continue stirring for a couple of minutes. Take out of the pan and set aside until ready to use.
In the same pan, sauté the cabbage and leeks. When they are soft and cooked through, finish with a splash of soy sauce.
Prepare noodles to package instructions. Rinse with cold water to stop cooking. Reserve some of the water you cooked the noodles in.
Mix the ingredients for the sauce in a bowl large enough to fit all the noodles: ginger, gochugaru or red chili flakes, sesame seeds, black pepper, peanut butter, soy sauce, rice vinegar. Heat ½ tbsp sesame oil over medium heat in a pan or ladle until it's hot. Add it to the bowl and let it sizzle.
Add a splash of the reserved noodle water to thin the sauce. Add the noodles to the sauce. Coat the noodles. Top with edamame, cabbage and leeks, more sesame seeds, and more chili flakes. Enjoy immediately!