Ingredients

• 1 1/2 pounds boneless sirloin steak
• Kosher salt and freshly ground pepper
• 1 tablespoon extra-virgin olive oil
• 1 tablespoon unsalted butter
• 2 sweet onions, sliced
• 1 tablespoon fresh thyme
• 1/3 cup low-sodium chicken broth
• 4 sub rolls, split
• 2 cups shredded gruyere cheese (about 6 ounces)
• 1 pint pickled or marinated vegetables (from the deli counter)

Instructions

1. Preheat the broiler. Generously season the steak with salt and pepper. Heat the olive oil in a large skillet over high heat. Add the steak and cook until browned, about 4 minutes per side for medium rare. Transfer to a cutting board and let rest.
2. Pour off any excess fat from the skillet and reduce the heat to medium. Melt the butter in the skillet, then add the onions, thyme, 1/2 teaspoon salt and a few grinds of pepper. Cook, stirring occasionally, until the onions start caramelizing, about 10 minutes. Stir in the chicken broth and cook until slightly reduced, about 5 minutes.
3. Meanwhile, trim off any excess fat from the steak; thinly slice against the grain. Put the rolls cut-sides up on a baking sheet and broil until toasted, about 2 minutes.
4. Remove the roll tops to a plate. Divide the onion mixture among the roll bottoms, top with the steak and sprinkle with the gruyere. Return to the broiler until the cheese is melted but not browned, 3 to 5 minutes. Top with the toasted roll tops and serve with the pickled vegetables.
5. Photograph by Ryan Dausch