Pan-Seared Rib-Eye Steak with Dijon Mushroom Sauce and Caramelized Onion Mashed Potatoes

This elegant yet comforting dish features a perfectly seared grass-fed rib-eye steak, topped with a luscious Dijon mushroom sauce. On the side, enjoy creamy mashed potatoes crowned with sweet caramelized onions and tender roasted carrots.

Inspired by classic steak Diane, this recipe brings bistro flavors home with simple techniques. The rich demi-glace sauce, enhanced with mustard and mushrooms, pairs beautifully with the hearty sides. Perfect for a special date night or a weekend dinner to impress.

Log in to save recipes and build weekly shopping lists.

Ingredients

1.5 tablespoon Sour CreamView ingredient guideLike ingredientDislike ingredient

16 ounce PotatoesView ingredient guideLike ingredientDislike ingredient

1 unit OnionView ingredient guideLike ingredientDislike ingredient

12 ounce CarrotView ingredient guideLike ingredientDislike ingredient

4 ounce Button MushroomsView ingredient guideLike ingredientDislike ingredient

16 ounce Grass-Fed Rib-Eye SteakView ingredient guideLike ingredientDislike ingredient

1 unit Beef Demi-GlaceView ingredient guideLike ingredientDislike ingredient

1 clove GarlicView ingredient guideLike ingredientDislike ingredient

2 teaspoon Dijon MustardView ingredient guideLike ingredientDislike ingredient

teaspoon (tsp) SaltView ingredient guideLike ingredientDislike ingredient

1 teaspoon (tsp) SugarView ingredient guideLike ingredientDislike ingredient

2 tablespoon (tbsp) Cooking OilView ingredient guideLike ingredientDislike ingredient

1 tablespoon (tbsp) ButterView ingredient guideLike ingredientDislike ingredient

teaspoon (tsp) Black PepperView ingredient guideLike ingredientDislike ingredient

Instructions

1. Adjust rack to top position and preheat oven to 425°F. Wash and dry produce. Trim, peel and cut carrots on a diagonal into 1-inch-thick pieces. Peel and dice potatoes into ½-inch pieces (peeling is optional). Halve, peel and thinly slice onion. Trim and thinly slice mushrooms. Peel and mince garlic.
2. 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 with sour cream until smooth. Season with salt and pepper. Keep covered off heat.
3. While potatoes cook, heat a large drizzle of oil in a large 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. Transfer to a small bowl. Wipe out pan.
4. Pat steak dry with paper towels; season generously with salt and pepper. Heat a large drizzle of oil in the same pan over medium-high heat. Add steak and cook to desired doneness, 5-7 minutes per side for medium-rare. Transfer to a cutting board to rest.
5. Add 1 TBSP butter and mushrooms to the same pan over medium-high heat. Cook, stirring, until browned and softened, 3-5 minutes. Add garlic and cook until fragrant, 30 seconds. Stir in demi-glace and ¼ cup water. Bring to a boil, then reduce to a simmer. Stir in mustard. Simmer until thickened, 2-3 minutes. Season with salt and pepper.
6. Slice steak against the grain. Divide potatoes, carrots and steak between plates. Top potatoes with caramelized onion. Spoon mushroom sauce over steak and serve.

Recipe Tips

FAQ

Can I use a different cut of steak?

Yes, you can substitute with sirloin or New York strip. Adjust cooking time accordingly.

What can I use instead of demi-glace?

You can replace demi-glace with 1 cup of beef broth simmered until reduced by half, then use as directed.

How do I make the mashed potatoes dairy-free?

Use a dairy-free sour cream alternative and substitute butter with olive oil or vegan butter.