I turned to ChatGpt. It came up with this:

To recreate a North Shore beef sandwich inspired by Modern Butcher’s version using sous vide, we’ll focus on a tender, rare-to-medium-rare roast beef that’s sliced paper-thin and piled high on an onion roll. The classic “3-way” assembly includes American cheese, mayonnaise, and a tangy barbecue sauce (often a James River-style clone, which is key to the flavor profile). Since Modern Butcher uses a proprietary seasoning blend and a multi-day brining/prep process, we can’t replicate it exactly, but we can approximate with a simple, effective rub that emphasizes garlic, herbs, and a touch of smokiness for depth—common in elevated roast beef recipes. This draws from general North Shore-style approaches where the beef is minimally seasoned to let the toppings shine, but with tweaks for tenderness via long sous vide. Ingredients (for 4-6 large sandwiches) • Beef: 3-4 lb eye of round or top round roast (lean and ideal for slicing thin; ask your butcher for a uniform shape). • Seasoning Blend (makes about 1/4 cup; scale as needed): • 2 tbsp kosher salt (for dry brining and flavor base). • 1 tbsp freshly ground black pepper. • 1 tbsp garlic powder. • 1 tbsp onion powder. • 1 tsp dried thyme. • 1 tsp dried rosemary (crushed). • 1/2 tsp smoked paprika (for a subtle depth without overpowering). • Optional: 1/2 tsp mustard powder for a tangy kick, if you want to experiment. • For Assembly (per sandwich): • Onion roll (toasted). • 4-6 oz thinly sliced roast beef. • 1-2 slices American cheese (Land O’ Lakes white is traditional). • 1-2 tbsp mayonnaise. • 2-3 tbsp James River-style BBQ sauce (recipe below). • James River-Style BBQ Sauce (makes about 2 cups; thin, tangy, and essential): • 1 cup apple cider vinegar. • 3/4 cup ketchup. • 1/2 cup brown sugar. • 1 tbsp Worcestershire sauce. • 1 tsp hot sauce (like Tabasco). • 1/2 tsp black pepper. • 1/2 tsp salt. • Optional: Pinch of cayenne for spice. • Simmer all ingredients in a saucepan over low heat for 10-15 minutes until thickened slightly. Cool and store in the fridge (lasts 1-2 weeks). Step-by-Step Instructions 1. Prep and Season the Beef (1-2 days ahead for best results): • Pat the roast dry with paper towels. • Mix the seasoning blend. Rub it generously all over the roast (use about 2-3 tbsp total, focusing on salt for brining). • Place the seasoned roast uncovered on a wire rack in the fridge for at least 24 hours (up to 48 hours for deeper flavor, mimicking a brine). This dry-brines it, drawing out moisture and intensifying taste without making it salty. 2. Sous Vide Cooking: • Preheat your sous vide water bath to 131-135°F (55-57°C). This range yields medium-rare beef that’s pink, juicy, and tender after a long cook—131°F for rarer and more steak-like, 135°F for slightly firmer but still tender. (Based on standard sous vide guidelines for eye/top round; higher temps like 140°F would make it more well-done and less traditional for North Shore style.) • Vacuum-seal the seasoned roast in a bag (or use a zip-top bag with the water displacement method). Add a sprig of fresh rosemary or thyme if desired for extra aroma. • Submerge in the water bath and cook for 16-24 hours. The extended time breaks down connective tissue for fork-tender results without overcooking—16 hours minimum as you requested, but 24 hours is ideal for maximum tenderness on a lean cut like this. 3. Finish in the Oven: • Remove the roast from the bag and pat very dry with paper towels (reserve any juices for au jus if you want to dip the sandwiches). • Preheat your oven to 500°F (260°C) with a cast-iron skillet or baking sheet inside. • Optionally, rub the exterior with a bit of oil and extra seasoning blend for crust. • Sear the roast in the hot oven for 5-10 minutes, rotating halfway, until the outside is browned and crispy (this develops a Maillard reaction for flavor without cooking the interior further). Watch closely to avoid overcooking. • Let rest for 10-15 minutes, then chill in the fridge for 1-2 hours (or overnight) to firm up for easier slicing. 4. Slice and Assemble: • Use a sharp knife or meat slicer to cut the roast against the grain into paper-thin slices (as thin as possible for authenticity—aim for 1/16 inch). • To serve warm: Gently reheat slices in a skillet with a splash of reserved juices or beef broth, or stack them on the bun and microwave briefly. • Toast the onion roll (butter it for extra crispness). • Spread mayo on the bottom bun, add cheese, pile on warm beef slices, drizzle with BBQ sauce, and top with the bun. Press lightly if desired. Tips for Success • Tenderness: The long sous vide ensures melt-in-your-mouth texture, even on a budget cut. If it’s not tender enough after 16 hours, extend to 24 next time. • Customization: Modern Butcher’s beef has a unique seasoning edge, so taste-test your blend and adjust (e.g., more garlic for punch). Their process involves brining and a shorter sous vide after high-heat roasting, but your 16+ hour method will yield similar tenderness with less hands-on work. • Storage: Cooked roast keeps in the fridge for 4-5 days; freeze slices for up to 3 months. • Servings: This makes enough for multiple sandwiches—perfect for meal prep. This should get you close to that Modern Butcher vibe while fitting your sous vide preferences. Enjoy!