Preheat oven to 300°F. Pat chuck roast dry with paper towels and season all sides with salt and pepper.
Heat 1 tablespoon olive oil in Dutch oven over medium-high heat. Sear roast 5-6 minutes per side until deeply browned on all sides. Remove to a plate.
Reduce heat to medium and add remaining oil. Add sliced onions with a pinch of salt. Cook 20-25 minutes, stirring occasionally, until golden and caramelized.
Stir in garlic and maple syrup. Cook 2 minutes until fragrant. Sprinkle flour over onions and stir for 1 minute.
Pour in wine and scrape up browned bits from bottom of pot. Add beef stock, rosemary, and bay leaves. Bring to a simmer.
Nestle roast back into pot. Liquid should come two-thirds up the sides. Cover tightly and transfer to oven.
Braise for 3 hours. Flip roast carefully, re-cover, and cook another 30-45 minutes until fork-tender.
Remove from oven. Discard rosemary and bay leaves. Let rest 10-15 minutes before serving with gravy.
