If not already thinly sliced, place steak in the freezer 20–30 minutes to firm up, then slice across the grain into thin strips about 1/8–1/4 inch thick. In a bowl combine 2 tbs olive oil, minced garlic, white wine vinegar, lemon juice, paprika, smoked paprika, oregano, optional hot paprika or cayenne, 1 tsp salt and 1/2 tsp black pepper. Add the sliced steak and toss to coat thoroughly. Cover and refrigerate for at least 30 minutes or up to 4 hours for more flavor.

Cook the steak

Heat a large heavy skillet or cast-iron pan over high heat until very hot. Add a little oil or wipe the pan with the remaining olive oil. Remove steak from marinade, letting excess drip off. Working in batches if necessary, add steak in a single layer and sear quickly, about 1–2 minutes per side, until browned but still tender. Do not overcook. Transfer seared steak to a plate and keep warm.

Prego Sauce (garlic butter sauce)

Make the sauce in the same pan

Reduce heat to medium and add 1 tbs olive oil and 3 tbs unsalted butter to the same skillet used for the steak (add a splash of beef stock if pan is dry). When butter melts and begins to foam, add the thinly sliced garlic and cook, stirring, until fragrant and just golden, about 1–1.5 minutes—do not burn. Stir in 1/4 cup beef stock, lemon zest, 1/4 tsp salt and red pepper flakes if using. Let sauce simmer 1–2 minutes to reduce slightly.

Finish sauce with parsley and combine

Return the seared steak and any juices to the pan. Toss to coat in the garlic butter sauce and heat through for 30–60 seconds. Stir in 2 tbs finely chopped parsley. Taste and adjust seasoning with salt and pepper as needed.

Sandwich Assembly

Prep rolls

Halve the rolls and spread each cut side lightly with the softened butter. If you like, toast the rolls face down in a clean skillet or under a broiler until golden and slightly crisp, about 1–2 minutes.

Assemble the Beef Prego

Divide the sauced steak evenly among the four rolls, piling the meat and spooning extra sauce over the top. Add optional sliced provolone or mozzarella and pickled or roasted peppers if using. Garnish with extra parsley. Close the sandwiches and press lightly.

Serve

Serve the Beef Prego immediately while hot. Provide extra sauce on the side and lemon wedges if desired.