Start by boiling water in a small pot and adding your soba noodles. Cook until they become tender but still maintain a slight bite. They are ready when they float to the top and smell nutty. Avoid overcooking them to prevent a mushy texture.
Once cooked, drain the noodles and rinse them under cold water in a colander. This step is crucial to prevent sticking and maintain that nice chewy texture.
In a small pan, heat olive or vegetable oil over medium heat. Add sliced onions and mushrooms, cooking until they soften and start to brown, about 3-4 minutes. The aroma will fill your kitchen.
Toss in the cooked edamame and chopped baby spinach into the skillet. Stir for just a couple of minutes until the spinach wilts and everything is heated through. Aim for vibrant colors without letting the spinach darken too much.
Drizzle in the soy sauce and lemon juice, and sprinkle granulated sugar over the mixture. This will create a nice glaze. Make sure to mix it well to evenly coat all ingredients.
Gently fold the noodle mixture into the veggie blend. Ensure a uniform distribution, so every forkful is satisfying. Be careful not to break the noodles apart.
Scoop the soba noodle salad onto plates. Add sliced red chili pepper on top for an extra kick if desired. Enjoy while it is still warm for the best flavor experience.