Heat the coconut oil in a large pot over medium-high heat. Cook pieces until golden brown on both sides, then remove. Stir in the red onion and garlic; cook until they soften and brown, about 6 minutes.
Pour in soy sauce, bay leaf, peppercorn, vegetable stock, and vinegar. Add the tempe and rice, increase the heat to high, and bring to a boil. Reduce heat to medium-low, cover, and simmer until the rice is about 30-40 minutes.