Preheat your oven to 350 degrees F.

Add the oil to a large Dutch oven or oven-proof pot over medium-high heat. Season both sides of the roast with salt and pepper, and coat evenly with flour. Sear the meat on both sides until a brown crust forms, about 5 minutes per side. Transfer the roast to a platter and set aside.

Lower the heat to medium-low and add the broth, coconut milk, soy sauce, curry paste, ginger, garlic, sugar, and fish sauce to the pot. Stir to mix. Gently place the beef in the pan, cover with the lid, and place in the oven to roast for 2 hours.

After two hours, remove the roast from the oven and carefully transfer the beef to a sheet pan. Skim about ¼ cup of fat from the sauce.

Shred the meat into chunks and pieces with two forks, then slide these pieces, along with the juices, back into the pot.

Add the sliced onion to the pot and allow the mixture to rest for about 5 minutes before serving. Serve the drip beef in bowls with rice or noodles, with extra drippings on the side.