Pat the beef chuck dry and heat oil in a Dutch oven over medium-high heat. Brown the beef in batches, cooking each side for 4-5 minutes.

Lower heat and add sliced onions, cooking for 5-7 minutes until translucent. Stir in minced garlic and sauté for 1-2 minutes.

Sprinkle flour over the onion mixture, stir well, and cook for about 2 minutes to create a roux.

Pour in dark beer, scraping the pot to deglaze. Let it simmer for 3-4 minutes.

Return the beef and juices to the pot, add broth, vinegar, sugar, thyme, and bay leaf. Stir and simmer over medium heat.

Reduce heat to low, cover, and let it simmer for 1.5 hours, stirring occasionally.

Remove from heat and let rest for 15 minutes before serving. Serve with crusty bread.