Instructions:
- Prepare the Beef: Slice the steak paper-thin against the grain. In a bowl, whisk together the soy sauce, brown sugar, sesame oil, grated ginger, 2 cloves minced garlic, and black pepper. Add the sliced beef, toss well to coat, and set aside to marinate for at least 15 minutes.
- Cook the Rice: Start cooking your rice according to package directions or using your rice cooker so it’s ready when the stir-fry is done.
- Sear the Beef: Heat half the high-heat oil in a large wok or skillet over high heat until just smoking. Remove the beef from the marinade (reserve any excess liquid) and sear in a single layer (work in batches if necessary) for 1-2 minutes per side until nicely browned. Remove the beef and set aside.
- Sauté Vegetables: Add the remaining oil to the same pan. Toss in the sliced onions and peppers. Stir-fry over medium-high heat for 4-5 minutes until they start to soften but still retain a good bite.
- Aromatics and Sauce: Push the vegetables to one side. Add the remaining 1 clove of minced garlic and the Gochugaru to the cleared space. Cook for 30 seconds until fragrant. Deglaze the pan by pouring in the reserved marinade liquid and the beef broth. Bring the sauce to a simmer, scraping up any browned bits from the bottom of the pan.
- Combine and Finish: Return the seared beef (and any resting juices) to the pan. Toss everything together quickly for about 1 minute until the beef is heated through and coated in the glossy sauce. Do not overcook at this stage.
- Serve: Divide the cooked rice among four bowls. Top generously with the beef and pepper mixture. Garnish immediately with sliced green onions and a sprinkle of sesame seeds.