Slice the yellow onions into thin rounds and mince the garlic. Season the beef chuck roast generously with salt and pepper on all sides.

In a Dutch oven, heat olive oil over medium-high heat. Sear the seasoned beef roast for about 10-12 minutes until browned on all sides. Remove and set aside.

Add sliced onions to the pot, reduce heat to medium, and cook for 5 minutes until translucent. Stir for 20 minutes until caramelized into deep golden brown.

Add minced garlic and cook for an additional 7-8 minutes. Stir in maple syrup and flour, then deglaze with red wine, scraping up bits from the bottom. Pour in beef broth.

Return the seared beef to the pot, add thyme and bay leaves, cover, and transfer to a preheated oven at 300°F. Simmer for 3 hours, flipping halfway through.

Remove from oven and let the roast rest for about 15-20 minutes. Shred the meat and mix it back into the onion mixture before serving.