01 - Preheat oven to 325°F.
02 - Pat beef chuck roast dry and season with salt, pepper, thyme, oregano, and paprika.
03 - In a Dutch oven or heavy-bottomed pot, heat vegetable oil over medium-high heat. Sear the roast on all sides until browned, about 2-3 minutes per side.
04 - Add sliced onion and garlic; sauté 2 minutes.
05 - Pour in beef broth and water. Add bay leaf. Bring to a simmer, cover, and transfer to oven. Braise for 2–2.5 hours, or until beef is fork-tender.
06 - Remove beef from pot and shred with two forks. Set aside.
07 - Strain and reserve 2 cups of the braising liquid for gravy.
08 - For the gravy: In a saucepan, melt butter over medium heat. Whisk in flour and cook, stirring, for 2 minutes.
09 - Gradually add strained beef cooking liquid, whisking constantly to avoid lumps. Simmer until thickened, about 5 minutes.
10 - Return shredded beef to gravy and stir to combine.
11 - Slice French bread loaves lengthwise. Optional: Spread mayonnaise on the inside of each loaf.
12 - Pile the hot roast beef with gravy onto each loaf. Top with shredded lettuce, tomato slices, and pickles.
13 - Add hot sauce if desired. Close sandwiches and serve immediately.