Classic Steak Diane with Mushrooms and Cognac Cream Sauce

Quick Recipe Version (TL;DR)

• Yield: 4 servings
• Prep Time: 20 minutes
• Cook Time: 20 minutes
• Total Time: 40 minutes

Quick Ingredients

• 1 1/2 lb beef tenderloin or top sirloin, cut into 8 thin medallions
• 1 tsp kosher salt, 1/2 tsp black pepper, pinch paprika (optional)
• 1 tbsp all-purpose flour (optional, light dusting)
• 1 tbsp neutral oil + 2 tbsp unsalted butter (divided)
• 8 oz cremini or white mushrooms, thinly sliced
• 1 small shallot, minced; 2 garlic cloves, minced
• 1/3 cup cognac or brandy
• 1/2 cup low-sodium beef broth
• 2 tbsp Dijon mustard + 1 tsp grainy mustard (optional)
• 2 tsp Worcestershire sauce
• 1/3 cup heavy cream
• 2 tbsp chopped fresh chives (plus extra to garnish)
• Salt, pepper, and optional lemon juice to taste

Do This

• 1. Pat steak dry, season with salt, pepper, and optional paprika; lightly dust with flour.
• 2. Heat 1 tbsp oil and 1 tbsp butter in a large skillet over medium-high; sear steak medallions 1–2 minutes per side until browned but still medium-rare. Transfer to warm plate, tent loosely with foil.
• 3. Lower heat to medium, add remaining 1 tbsp butter, mushrooms, and a pinch of salt; sauté until browned and most liquid evaporates.
• 4. Add shallot and garlic; cook 1 minute. Off the heat, add cognac, then carefully return pan to burner and let it flame or simmer until reduced by about half.
• 5. Stir in beef broth, Worcestershire, Dijon (and grainy mustard if using); simmer 2–3 minutes until slightly thickened.
• 6. Add heavy cream and any juices from resting steak; simmer gently 2–3 minutes until silky. Season with salt, pepper, and a squeeze of lemon if desired.
• 7. Return steak and accumulated juices to pan, turning to coat and warming 1–2 minutes. Stir in chives, plate steak, spoon sauce and mushrooms over top, and serve immediately.

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Why You’ll Love This Recipe

• It feels like a fancy steakhouse classic but cooks in under 30 minutes once you start.
• The cognac, mustard, and cream make a rich, velvety pan sauce that tastes way more complex than the effort involved.
• Thin medallions cook quickly, so you get perfectly tender steak without babysitting a grill.
• It is ideal for an elegant retro dinner party centerpiece, yet approachable enough for a cozy date night at home.

Grocery List

• Produce: 8 oz cremini or white mushrooms, 1 small shallot, 2 garlic cloves, 1 small bunch fresh chives, 1 small bunch fresh parsley (optional), 1 lemon (optional), side vegetables of choice (green beans, salad greens, etc.).
• Dairy: Unsalted butter, heavy cream.
• Pantry: 1 1/2 lb beef tenderloin or top sirloin, kosher salt, black pepper, paprika (optional), all-purpose flour (optional), neutral oil (canola, vegetable, grapeseed), cognac or brandy, low-sodium beef broth, Dijon mustard, grainy mustard (optional), Worcestershire sauce.

Full Ingredients

For the Steak

• 1 1/2 lb (680 g) beef tenderloin or top sirloin, trimmed and cut into 8 medallions, about 3/4 inch (2 cm) thick
• 1 tsp kosher salt, plus more to taste
• 1/2 tsp freshly ground black pepper
• 1/4 tsp paprika (optional, for color and mild warmth)
• 1 tbsp all-purpose flour (optional, for a light crust and to help thicken the sauce)
• 1 tbsp neutral oil (canola, vegetable, or grapeseed)
• 1 tbsp unsalted butter

For the Diane Mushroom Sauce

• 1 tbsp unsalted butter
• 8 oz (225 g) cremini or white button mushrooms, thinly sliced
• 1 small shallot, finely minced (about 2 tbsp)
• 2 garlic cloves, minced
• 1/3 cup (80 ml) cognac or brandy
• 1/2 cup (120 ml) low-sodium beef broth or stock
• 2 tbsp Dijon mustard
• 1 tsp grainy mustard (optional, for texture and extra tang)
• 2 tsp Worcestershire sauce
• 1/3 cup (80 ml) heavy cream
• 1 tsp fresh lemon juice (optional, to brighten the sauce)
• 2 tbsp finely chopped fresh chives, plus extra for garnish
• 1 tbsp finely chopped fresh parsley (optional, for color)
• Salt and freshly ground black pepper, to taste

To Serve (Optional but Recommended)

• Mashed potatoes, buttered baby potatoes, or buttered egg noodles
• Green beans, asparagus, or a simple green salad

Step-by-Step Instructions

Step 1: Prep the Steak and Ingredients

Pat the beef medallions very dry with paper towels. This helps them brown properly instead of steaming in the pan. In a small bowl, mix the kosher salt, black pepper, and paprika (if using). Season both sides of each medallion evenly. If you like a slightly thicker, more restaurant-style crust and sauce, lightly dust each side with a very thin coating of flour, tapping off any excess.

Let the seasoned steak sit at room temperature for about 10–15 minutes while you prepare the other ingredients. This takes the chill off and promotes more even cooking. Slice the mushrooms, mince the shallot and garlic, and chop the chives (and parsley, if using) so everything is ready to go once you start cooking.

Step 2: Sear the Steak Medallions

Heat a large, heavy skillet (stainless steel or cast iron is ideal) over medium-high heat until hot. Add the neutral oil and 1 tbsp butter. When the fat is shimmering and the butter foam has just subsided, lay the steak medallions in the pan in a single layer without crowding. You may need to work in two batches, depending on pan size.

Sear for 1–2 minutes on the first side until nicely browned, then flip and sear for another 1–2 minutes on the second side. Because the pieces are thin, this is usually enough to reach medium-rare (about 125–130°F / 52–54°C). Adjust time slightly if you prefer more or less doneness, but keep in mind they will warm again briefly in the sauce.

Transfer the seared steaks to a warm plate and tent loosely with foil to keep them warm while you make the sauce. Do not wipe out the pan; the browned bits are pure flavor.

Step 3: Sauté the Mushrooms and Aromatics

Reduce the heat to medium. Add the remaining 1 tbsp butter to the same skillet. Once melted, add the sliced mushrooms and a small pinch of salt. Cook, stirring occasionally, for 5–7 minutes until the mushrooms release their liquid, the liquid mostly evaporates, and the mushrooms take on a deep golden-brown color.

Add the minced shallot and cook, stirring, for about 1 minute until softened and fragrant but not browned. Then add the minced garlic and cook for another 30 seconds, stirring constantly so it does not burn. You should have a pan full of fragrant, lightly caramelized mushrooms and aromatics, with browned bits sticking to the bottom of the pan.

Step 4: Deglaze and (Optionally) Flambé with Cognac

Carefully remove the pan from the heat. Pour in the cognac or brandy. Tilt the pan slightly away from you to avoid any splashes. If you are comfortable flambéing, you can ignite the cognac with a long lighter or match, keeping your face and hair well away from the pan. The flames will burn off the alcohol in 10–20 seconds. Gently swirl the pan until the flames subside.

If you prefer not to flambé, simply return the pan to medium heat and let the cognac simmer briskly for 1–2 minutes, scraping up the browned bits from the bottom of the pan with a wooden spoon. Either way, reduce the liquid by about half; it should smell rich and slightly sweet, without harsh alcohol vapors.

Step 5: Build the Mustard-Cream Diane Sauce

Once the cognac has reduced, add the beef broth, Worcestershire sauce, Dijon mustard, and grainy mustard (if using). Whisk or stir until the mustards dissolve into the liquid. Let this mixture simmer over medium heat for 2–3 minutes, reducing slightly and concentrating the flavors.

Reduce the heat to medium-low and stir in the heavy cream. Simmer gently, stirring occasionally, for another 2–3 minutes until the sauce thickens enough to lightly coat the back of a spoon. If it seems too thick, add a splash more beef broth; if too thin, continue simmering. Taste the sauce and season with salt and freshly ground black pepper. Add a small squeeze of lemon juice, if using, to brighten the richness.

Step 6: Return the Steak to the Pan and Finish

Pour any accumulated juices from the plate of resting steak into the sauce and stir to combine. Slide the seared steak medallions back into the pan, nestling them into the mushrooms and sauce in a single layer. Spoon some sauce over the top of each piece.

Cook over low heat for 1–2 minutes, just until the steaks are warmed through and coated in the sauce. Avoid vigorous boiling at this point to prevent overcooking the meat or breaking the cream. Stir in the chopped chives and parsley (if using), reserving a little for garnish.

Step 7: Plate and Serve

Taste the sauce one last time and adjust seasoning with additional salt, pepper, or lemon juice as needed. The sauce should be silky, rich, and balanced with savory depth from the mushrooms and Worcestershire, gentle sweetness from the cognac, and subtle tang from the mustard.

To serve, place a bed of mashed potatoes, buttered baby potatoes, or egg noodles on each warmed plate. Arrange 2 steak medallions per person on top or alongside, then spoon plenty of mushroom-Diane sauce over the meat and starch. Finish with a sprinkle of fresh chives and any remaining parsley. Serve immediately while hot, alongside your favorite green vegetable or a simple salad.

Pro Tips

• Get the pan hot first: Proper browning happens in a hot pan with dry meat. Pat the steak dry and wait until the oil is shimmering before adding it.
• Do not overcook the medallions: Because they are thin, they cook quickly. Pull them at medium-rare; they will warm through again in the sauce.
• Flambé safely (or skip it): Always remove the pan from the burner before adding cognac and ignite with a long lighter. If flames make you nervous, simply simmer to reduce instead.
• Use low-sodium broth: The sauce reduces and can become salty if your broth is highly seasoned. You can always add salt at the end but you cannot take it out.
• Slice mushrooms evenly: Thin, even slices cook more uniformly and soak up the Diane sauce beautifully.

Variations

• Ribeye or strip Diane: Use 4 small ribeye or New York strip steaks instead of medallions. Sear them to your preferred doneness, then prepare the sauce as written and spoon over the steaks.
• Brandy and green peppercorn version: Swap cognac for brandy and add 1–2 tsp drained green peppercorns to the sauce for a subtle peppery kick.
• Lighter version: Use half-and-half instead of heavy cream and reduce the amount to 1/4 cup. The sauce will be a bit lighter but still flavorful.

Storage & Make-Ahead

This dish is best eaten fresh, as the steak can overcook when reheated. However, leftovers can be stored in an airtight container in the refrigerator for up to 2 days. Reheat very gently in a skillet over low heat, adding a splash of broth or cream to loosen the sauce, and warm just until the steak is heated through.

For make-ahead prep, you can slice the mushrooms, mince the shallot and garlic, chop the herbs, and trim and cut the beef into medallions several hours in advance. Store each component separately in the refrigerator. Do not season or flour the steak until just before cooking, as salt can draw out moisture if it sits too long.

Nutrition (per serving)

Approximate values for 1 of 4 servings (steak and sauce only, not including sides): about 650 calories; 43 g fat; 15 g saturated fat; 8 g carbohydrates; 1 g fiber; 3 g sugar; 48 g protein; 860 mg sodium (will vary depending on broth and added salt).