In a small baking dish or shallow bowl, combine 2 tablespoons soy sauce with 2 tablespoons cornstarch. Add the tofu and toss to coat. Allow to marinate for 15-30 minutes while you prepare the other ingredients.
Make kung pao sauce
In a medium bowl, whisk together all of the sauce ingredients until combined. Set aside.
In a large skillet or wok, heat 1 tablespoon grapeseed oil over medium high heat. Add the tofu and cook, stirring, until lightly browned on all sides, about 3-4 minutes. Transfer the tofu to a bowl and return the pan to the heat.
If necessary, add another teaspoon of grapeseed oil to the pan. Add the onion, green bell pepper, and red bell pepper. Cook, stirring frequently, for 4 minutes.
Add the garlic and ginger and cook, stirring, 30 seconds more.
Return the tofu to the pan and add the sauce. Stir to combine and cook, stirring frequently, until hot and thick, about 2 minutes.
Remove from the heat and top with scallions and peanuts before serving.
Tips for customizing
Make this dish spicier and more authentic by swapping the sambal oelek for 5-6 dried red chiles, added with the garlic and ginger
You can skip the red and green bell pepper (or swap one for the other) if you don’t have them on hand, or serve them on the side
Adjust the spiciness of this dish by increasing or decreasing the amount of sambal oelek or drizzling with sriracha before serving
Use soy sauce instead of tamari if you don’t care about it being gluten-free
Swap the coconut sugar for brown sugar or maple syrup