Preheat oven to 300 degrees F.

Pat dry chuck roast and season with Kosher salt and ground black pepper on both sides.

In a large Dutch oven, heat oil over medium-high heat and sear chuck roast on both sides until golden brown, about 5 minutes per side. Remove and set aside.

Reduce heat to medium, melt butter in the same pot, add sliced onions, and cook for 25-30 minutes, stirring occasionally.

Add minced garlic and cook for an additional 2 minutes. Stir in white wine and let it reduce by about half.

Sprinkle flour over the mixture and stir to coat.

Add beef broth, Worcestershire sauce, bay leaves, and herb sprigs. Bring to a simmer and season with salt and pepper.

Return chuck roast to the pot, ensuring the liquid covers about ? of the beef. Add more broth if necessary.

Cover tightly and braise in the oven for 3.5 hours until tender. Cook for an additional 20 minutes for more tenderness if desired.

Remove from the oven, increase temperature to 400 degrees F.

Shred beef into smaller chunks, discarding excess fat and bay leaves.

Top with shredded Gruyere cheese and return to the oven until cheese is melted, about 5-7 minutes.

Serve warm over mashed potatoes or with toasted baguette slices.