Rustic Rib-Eye On Ciabatta

• 3 (8 ounce) rib-eye steaks
• 3 tablespoons butter, or as needed (optional)
• salt and ground black pepper to taste (optional)
• 1 tablespoon butter
• 1 tablespoon garlic oil
• 1 teaspoon brown sugar
• 1 large onion, halved and thinly sliced
• 1 tablespoon red wine vinegar
• 5 tablespoons prepared pesto sauce
• 2 tablespoons mayonnaise
• 2 teaspoons lime juice
• 1/4 cup butter, melted
• 1/4 teaspoon onion powder
• 1/4 teaspoon garlic powder
• 1 pinch salt
• 1 loaf ciabatta bread, split in half horizontally
• 4 slices Muenster cheese

1. Coat steaks with 1 tablespoon butter each; season with salt and pepper. Place each steak in a vaccum-seal bag. Seal the bags and place in a water bath with a sous vide cooker inserted. Set temperature to 130 degrees F (54 degrees C); cook until firm and reddish-pink and juicy in the center, about 1 hour.
2. Combine 1 tablespoon butter, garlic oil, and brown sugar in a large nonstick skillet over medium heat until butter is melted, about 1 minute. Place onion into the pan in a single layer; cook until translucent, about 5 minutes. Add vinegar; cover and reduce heat to low. Cook, adding a splash of water if needed, until onions are golden brown, about 20 minutes.
3. Combine pesto sauce, mayonnaise, and lime juice in a bowl. Stir until well combined. Cover with plastic wrap and refrigerate until ready to use.
4. Preheat oven to 325 degrees F (165 degrees C).
5. Stir melted butter, onion powder, garlic powder, and salt together in a bowl. Brush mixture over both halves of the bread. Place bread on a baking sheet; add Muenster cheese to 1 piece.
6. Bake in the preheated oven until golden brown, about 15 minutes.
7. Heat a grill pan over medium-high heat. Remove 1 steak from the bag and cook on the grill pan until nicely browned, about 1 minute per side. Repeat with the remaining steaks. Let rest until set, about 5 minutes. Slice thinly against the grain.
8. Spread pesto mixture over the bread; add the steak and browned onions. Cut sandwich into 6 pieces.

butter, salt, butter, garlic oil, brown sugar, onion, red wine vinegar, pesto sauce, mayonnaise, lime juice, butter, onion powder, garlic, salt, bread, muenster cheese

Taken from www.allrecipes.com/recipe/260590/rustic-rib-eye-on-ciabatta/ (may not work)