Slice the tempeh into thin strips or cubes, depending on your preference.
In a bowl, combine the soy sauce, brown sugar, minced garlic, minced ginger, ground coriander, ground cumin, ground turmeric, and chili flakes (if using).
Add the tempeh slices to the marinade and toss to coat evenly. Let it marinate for at least 15 minutes, or up to an hour for more flavor.
Heat the vegetable oil in a skillet over medium heat.
Add the marinated tempeh to the skillet. Cook, turning occasionally, until the tempeh is golden brown and crispy on all sides, about 5-7 minutes.
Add water to the skillet to deglaze and create a sauce. Stir and let the sauce simmer for a few minutes until slightly thickened.
Enjoy your meal!