Step 1

In a large skillet, melt 2 tablespoons of the butter with 1 tablespoon of the olive oil over medium heat. Add the onions and cook, stirring occasionally, until golden, about 15 minutes. Transfer the onions to a bowl and set aside.

Step 2

Generously season both sides of the steak with salt and pepper. Add the remaining 1 tablespoon of the oil to the skillet and fry the steak over medium heat, turning once, until browned, about 6 minutes per side for medium. Transfer the steak to a serving platter and cover to keep warm.

Step 3

Add the bourbon to the skillet and, over medium heat, scrape up any bits that cling to the pan. Allow the liquor to simmer until reduced by half, about 1 minute. Add the onions and the remaining 2 tablespoons of butter and stir until the butter is melted. Reduce the heat and gently simmer until the onions are heated through, about 2 minutes. Season, to taste, with salt and pepper and stir in any juices that have run off from the steak.

Step 4

To serve, cut the steak into 1/4-inch-thick slices and top with the onions.