Slice your ribeye into thin strips to your liking. Peel and slice onions into rings.
In a medium bowl, marinate the ribeye with dark soy sauce (regular soy sauce is ok in a pinch), lemon juice, and pepper. Ideally you want to marinate for 30 minutes.
In a pan, heat oil and toss in the onions. Sauté until they begin to brown.
Add the marinated ribeye and all the sauce into the pan. Add sugar and a pinch of salt to taste. Adjust the flavor as you want. Cook for about 20 minutes on low heat or until the beef reaches your desired doneness.
Once done cooking, enjoy with vegetables and rice!
