Combine all the sauce ingredients in a large bowl.
Slice tofu into thin strips and gently add it to the sauce, making sure each piece of tofu gets coated. Allow the tofu to marinate in the sauce while you prepare the other ingredients.
Bring a large pot of water to a boil for your noodles and slice your onion, carrot, and mushrooms.
Add noodles to the boiling water and cook as per the package (usually around 8 minutes). Drain in a colander and rinse with cold water. Transfer to a bowl and use kitchen shears to cut the noodles down to 6-8 inches. Drizzle the noodles with sesame oil so they don’t stick. Let sit.
Heat up a large skillet with another drizzle of sesame oil. When hot, gently lift the tofu out of the marinade and place in your skillet. Cook until browned for 3-4 minutes per side. Remove the tofu from the skillet and set aside.
Add the onions to the skillet. Cook for 1 minute. Add carrots, stir, and cover, allowing to steam for 3 minutes. Add spinach, about ¼ of the sauce, and the mushrooms. Cook for another 2 minutes.
Add the noodles and the sauce. Gently toss everything to combine. Cook for another 1-2 minutes to combine all the flavours.
Add to your serving dish, top with tofu, and toasted sesame seeds! Drizzle with extra tamari, chilli garlic sauce, or a touch of sesame oil if desired.
