Steak “Diane” with Dijon-Mushroom Sauce

• 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, stirring occasionally, 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 with salt and pepper. • Heat a large drizzle of oil in same pan 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 (2 TBSP for 4 servings) and mushrooms to same pan over medium-high heat. Cook, stirring, until browned and softened, 3-5 minutes. • Add garlic and cook, stirring, until fragrant, 30 seconds. • Stir in demi-glace and ¼ cup water (1⁄3 cup for 4). Bring to a boil, then reduce to a simmer. • Stir in mustard. Simmer until thickened, 2-3 minutes. Season with salt and pepper.