Cooking Steps

• Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Dice potatoes into ½-inch pieces. Thinly slice chives. Place garlic cloves in the center of a small piece of foil; drizzle with olive oil and season with salt and pepper. Cinch into a packet.
• Place garlic foil packet on a baking sheet. Roast on top rack for 10 minutes. After 10 minutes, carefully add green beans to sheet; toss with a large drizzle of olive oil, salt, and pepper. Return to oven until garlic has softened and green beans are browned and tender, 12-15 minutes.
• While garlic roasts, place potatoes in a large pot with enough salted water to cover by 2 inches. Boil until tender when pierced with a fork, 15-20 minutes. Reserve 1 cup potato cooking liquid, then drain and return potatoes to pot. Mash until smooth, then stir in sour cream, salt, and pepper. If needed, add reserved potato cooking liquid a splash at a time until potatoes are creamy. Keep covered until ready to serve.
• While green beans roast, pat steak very dry with paper towels; season with salt and pepper. Heat a drizzle of oil in a large pan over medium-high heat. Once oil is hot, add steak and cook to desired doneness, 3-6 minutes per side, depending on thickness of meat. (TIP: If steak has a layer of fat on one side, use tongs to flip meat and sear until fat is rendered and crispy.) Turn off heat; transfer to a cutting board to rest. Wipe out pan.
• Once garlic is done, transfer to a cutting board and mash with a fork. Melt 1 tablespoon butter (2 tablespoon for 4 servings) in pan used for steak. Add mashed garlic (start with half and add more if desired); cook for 30-60 seconds. Add demi-glace and ¼ cup water (⅓ cup for 4). Simmer until slightly thickened, 1-2 minutes. Turn off heat. Stir in another 1 tablespoon butter (2 tablespoon for 4) and any resting juices from steak. Season with salt and pepper.
• Slice steak against the grain. Stir half the chives into potatoes. Divide potatoes, green beans, and steak between plates. Top steak and potatoes with sauce. Garnish with remaining chives.