Pan searing produces a steak that has a brown, crispy surface, and keeps your meat tender and juicy on the inside. Delmonico steak has sufficient fat to produce a moist, tender result when cooked with this method.
Season both sides of steak with salt and pepper and rub with olive oil.
Heat grill pan or skillet over medium-high heat. Add olive oil. When pan is hot, add onions and steak. Sear for 15-20 minutes, occasionally flipping the steak.
Mix paste ingredients until well combined. When the steak has been cooking for 20 minutes, brush paste over steak and onions on both sides.
Sear steak for an additional 10 minutes. Remove from heat and serve steak topped with onions.
For a medium to rare cook, sear for 25-30 minutes total. For a well-done steak, sear for an additional five minutes. A considerable number of recipes caution against overcooking the Delmonico steak as this may cause it to lose a significant amount of flavor and tenderness.