• Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce. • Trim, peel, and cut carrots on a diagonal into 1-inch-thick pieces. Peel and dice potatoes into 1⁄2-inch pieces. (TIP: For speedier spud prep, skip the peeling.) Halve, peel, and thinly slice onion. Trim and thinly slice mushrooms. (Skip if your mushrooms are pre-sliced!) Peel and mince garlic.

• Toss carrots on a baking sheet with a large drizzle of oil, salt, and pepper. • Roast on top rack until browned and tender, 25-30 minutes. • Meanwhile, place potatoes in a medium pot with enough salted water to cover by 2 inches. Bring to a boil; cook until tender, 15-20 minutes. • Drain and return potatoes to pot. Mash potatoes with sour cream until smooth. Season with salt and pepper. • Keep covered off heat until ready to serve.

• While potatoes cook, heat a large drizzle of oil in a large, preferably nonstick, pan over medium-high heat. Add onion and cook, stirring occasionally, until browned and softened, 8-10 minutes. • Add 1 tsp sugar and a splash of water; cook until caramelized, 2-3 minutes more. Season with salt and pepper. • Turn off heat; transfer to a small bowl. Wipe out pan.

• Pat steak* dry with paper towels; season all over with salt and pepper. • Heat a large drizzle of oil in pan used for onion over medium-high heat. Add steak and cook to desired doneness, 5-7 minutes per side. • Transfer to a cutting board to rest.

• Add 1 TBSP butter and mushrooms to pan used for steak over medium-high heat. Cook, stirring, until softened, 3-5 minutes. • Add garlic and cook until fragrant, 30 seconds. • Stir in demi-glace and 1⁄4 cup water (1⁄3 cup for 4 servings). Bring to a boil, then reduce to a simmer. • Stir in mustard. Simmer until thickened, 2-3 minutes. Season with salt and pepper.

• Slice steak against the grain. • Divide mashed potatoes, carrots, and steak between plates. Top potatoes with caramelized onion. Top steak with mushroom sauce and serve.