Heat 2 tablespoons of the oil in a large wok or sauté pan over medium-high heat. Once the oil is hot, add the onion and garlic, and sauté, stirring often, until the onion is translucent, 5 to 6 minutes. Add the rehydrated beef slices and continue to stir-fry until the slices are heated through and slightly crisp around the edges. (Note: if using a wok made from carbon steel or cast iron, transfer the onion and beef slices to a large non-stick sauté pan over medium heat – since the sauce for bistek is acidic due to the lemon, it can affect the seasoning in your wok.)

Add the soy sauce, broth, lemon juice, coconut sugar, cornstarch slurry and pepper to the pan mixing well to combine. Bring to a simmer and reduce the heat to medium-low until the sauce thickens and reduces by half, 10 to 15 minutes.

Meanwhile, heat the remaining tablespoon of oil in a separate large pan over medium high heat. Once the oil is hot, add the onion rings and cook until slightly tender, but not too soft, 4 to 6 minutes. Transfer the onion rings to the pan with the bistek and toss to combine. Serve with rice, garnish with green onion, and enjoy immediately!