Sous Vide Short Rib Melt with Gruyere and Caramelized Onions
- 1 pound boneless beef short ribs
- Kosher salt and freshly ground black pepper
- 1 tablespoon extra virgin olive oil
- 6 tablespoons unsalted butter
- 1 large yellow onion, thinly sliced
- 3 tablespoons Dijon mustard
- 3 tablespoons mayonnaise
- 8 slices sourdough or whole-grain bread
- 8 slices Gruyere cheese
Set the Sous Vide to 130°F (54.4°C).
Season the short ribs liberally with salt and pepper. Heat oil in a large skillet over high heat until smoking. Add short ribs and sear until golden brown on all sides. Transfer to a plate and let cool for 10 minutes.
Place cooled ribs in a large zipper lock or vacuum seal bag. Seal the bag using the water immersion technique or a vacuum sealer the moist setting. Place in the water bath and set the timer for 4 hours.
When the timer goes off, remove the bag from the water bath. Remove the short ribs from the bag, let rest for 10 minutes, and thinly slice against the grain. Discard cooking liquid.
Melt 2 tablespoons butter in a large non-stick skillet over medium heat. When the butter stops foaming, add the onions and season with salt and pepper. Cook, stirring occasionally, until the onions are golden brown, about 20 minutes.
In a small bowl, whisk together the mustard and mayonnaise. Spread evenly on one side of each piece of bread. Layer each sandwich with cheese, ribs, and onions.
Spread the remaining butter on the outside of each sandwich. Toast in a panini press or nonstick skillet until golden brown and cheese is melted. Serve.