Pat the beef chuck roast dry with paper towels, then season generously with salt, pepper, and cinnamon on all sides.
Heat olive oil in a heavy-bottomed Dutch oven over medium-high heat until shimmering. Add the beef and sear each side for about 4-5 minutes, until a deep golden-brown crust forms. Remove the beef and set aside.
Add sliced onions, chopped carrot, and celery to the same pot. Sauté for about 5 minutes until the vegetables soften slightly and release fragrant aromas.
Stir in the minced garlic and cook for another minute until fragrant, ensuring it doesn’t burn.
Return the seared beef to the pot, laying it on top of the vegetables. Pour the apple cider over the meat, making sure it's about halfway covered.
Bring the mixture to a gentle simmer, then cover the pot with a lid and lower the heat to maintain a low simmer. Cook for 2.5 to 3 hours until the beef is fork-tender and easily pulls apart.
Once cooked, transfer the beef to a cutting board and shred it into chunks or slices, depending on preference.
Optional: Skim any excess fat from the surface of the gravy, then stir to incorporate the caramelized vegetable juices.
Taste the gravy and adjust seasoning with salt, pepper, or a splash of extra cider if you wish for more tang.
Serve the shredded beef topped with the rich cider gravy and cooked vegetables, accompanied by your favorite side dishes.