• Adjust rack to middle position and preheat oven to 450 degrees. Wash and dry produce. • Slice potatoes into 1/4-inch-thick rounds. Halve, peel, and finely chop half the shallot (all for 4 servings). • In a small bowl, whisk together half the vinegar (you’ll use the rest later), 1 TBSP olive oil (2 TBSP for 4), and 1/2 tsp sugar (1 tsp for 4). Season with salt and pepper.

• Lightly oil a baking sheet. • In a large bowl, combine potatoes, garlic powder, 2 TBSP olive oil (4 TBSP for 4 servings), a couple big pinches of salt, and pepper; toss until potatoes are completely coated. Arrange on prepared sheet into clusters (about six slightly overlapping slices each). • Roast on middle rack for 12 minutes. Remove from oven; sprinkle with Parmesan. • Return to oven; roast until potatoes are tender and cheese is lightly browned, 10-12 minutes more.

• While potatoes roast, pat steak* dry with paper towels; season all over with salt and pepper. • Heat a large drizzle of oil in a large pan over medium-high heat. Add steak and cook to desired doneness, 5-7 minutes per side. • Turn off heat; transfer to a cutting board to rest. Wipe out pan.

• Heat a drizzle of oil in same pan over medium heat. Add shallot; cook, stirring, until softened, 1-2 minutes. • Pour in remaining vinegar. Simmer until reduced by half, 30 seconds. • Stir in stock concentrate and 1/4 cup water (1⁄3 cup for 4 servings). Simmer until thickened, 2-3 minutes. • Turn off heat. Stir in sour cream and 1 TBSP butter (2 TBSP for 4) until melted and combined. Season with salt and pepper.

• In a second large bowl, toss mixed greens with as much vinaigrette as you like. Season with salt and pepper.

• Slice steak against the grain. • Divide steak, potato clusters, and salad between plates. Top steak with sauce and serve. Steak is fully cooked when internal temperature reaches 145°.