Preheat your oven to 350°F (175°C) and position the rack in the lower third.

Pat the chuck roast dry with paper towels and season all sides with kosher salt.

In a large Dutch oven, heat vegetable oil over medium-high heat; brown the roast on all sides for about 10 minutes.

Reduce heat to medium and add sliced sweet onion; cook for about 4 minutes until softened.

Stir in minced garlic and grated ginger; cook for 1 minute until fragrant, deglazing with beef stock if necessary.

Mix in gochujang paste, brown sugar, and soy sauce, cooking for about 1 minute.

Return the browned roast to the pot, add remaining beef stock, and simmer for 5 minutes.

Cover and transfer to the oven; cook for 2 hours or until very tender.

Let the roast rest for 10-15 minutes before slicing.