Drain the tofu and slice into 3 equal parts. Pat the tofu dry, carefully, on both sides. Sprinkle a generous amount of salt on each side of the tofu, gentling patting the salt into the tofu. Tear off a little piece of tofu and taste it. If it's bland, add more salt. Cut the 3 slabs of tofu into cubes.
Heat 2 tablespoons of coconut oil over medium-high heat, in a large skillet.
Add the tofu and cook until the tofu is nicely browned on each side, approx 5-7 minutes (depending on how hot your pan is). Gently move the tofu around with a spatula, frequently, to ensure even browning and no burning.
When the tofu is nicely browned, put it on a paper towel lined plate, and let drain.
Heat another tablespoon of coconut oil in the same skillet (no need to wipe out the pan). Add the mushroom in a single layer...if you can and cook, without stirring, for 5-7 minutes, so the mushrooms can caramelize. Stir the mushrooms and add a good pinch of salt and pepper. Stir.
Transfer the mushrooms to a plate and set aside.
Add more coconut oil, if needed, once it's melted, add the garlic and ginger. Turn the heat down to medium. Constantly stir the ginger and garlic until they become fragrant, which will take approx 30 seconds.
Now add the red pepper and cook, stirring frequently, until the red pepper is soft, approx 5-7 minutes. Turn down the heat if need be to prevent burning the garlic and ginger.
When the rep pepper is almost cooked to your liking...add the white parts of the green onion and cook for another couple of minutes.
Now add the spinach, in small batches, and stir until ALL of the spinach is wilted.
Add the tofu, mushrooms, and green onion. Add the optional sauce..if using...and mix everything together. Cook a few minutes so the sauce and ingredients can marry a bit.
Before adding salt, squeeze lemon juice, from half a lemon, into the pan. Stir and taste.....now adding more lemon juice or salt and pepper to taste.
Finish the dish by stirring in a big handful of cilantro, if using
Serve stir fry over rice or quinoa.
Add additional soy sauce and Sriracha as you see fit, and enjoy!