Preheat the Oven: Begin by preheating your oven to 350°F (175°C) to get it ready for slow-roasting the beef.
Make the Marinade: In a large mixing bowl, whisk together the soy sauce, gochujang, sesame oil, brown sugar, minced ginger, and garlic until the mixture is smooth and well combined.
Marinate the Roast: Generously rub the marinade all over the chuck roast, ensuring it is evenly coated. Let it marinate at room temperature for at least 30 minutes, or preferably up to overnight in the refrigerator to enhance the flavors.
Sear the Meat: In a large Dutch oven, pour in a drizzle of sesame oil and heat it over medium-high heat. Once the oil is hot, carefully sear the roast on all sides until it achieves a deep brown color, taking about 3-4 minutes per side.
Sauté the Vegetables: After browning the roast, remove it from the pot and set it aside on a plate. In the same pot, add the sliced onions and sauté for about 3 minutes until they start to soften.
Combine Ingredients: Add the chopped carrots and beef broth to the pot, stirring thoroughly to combine. Return the seared roast back to the pot, nestling it amongst the vegetables.
Roast in the Oven: Cover the pot with a lid and transfer it to the preheated oven. Let it roast for approximately 3-4 hours, or until the meat is fork-tender and easily shreds.
Thicken the Sauce: If you prefer a thicker sauce, carefully remove the pot from the oven after roasting. Allow the roast to rest for about 15 minutes. In a small bowl, mix cornstarch with a splash of cold water to create a slurry. On the stovetop, heat the pot juices over medium heat and stir in the slurry until the sauce thickens to your desired consistency.
Slice and Serve: After the roast has rested, slice it against the grain into thick pieces. Serve the sliced beef drizzled with the rich, thickened sauce for maximum flavor exposure.
Notes
Serve over rice or noodles and garnish with green onions and sesame seeds.