Steak Sandwich with Peppercorn Au Poivre Sauce

This sandwich is everything you want when you’re craving something substantial: grilled steak, caramelized onions, sautéed mushrooms and a rich au poivre sauce that ties it all together. It’s indulgent, bold, and absolutely worth the effort when you want to treat yourself. The result is a hefty, flavor-packed sandwich that satisfies big appetites.

It’s not difficult to make and pulls out all the stops. Here’s how to build this steak sandwich with au poivre sauce at home.

What is au poivre sauce?

Au poivre is a classic French pepper sauce, traditionally made from heavy cream, beef stock, and plenty of coarsely cracked black pepper. The name literally means “with pepper,” and the sauce delivers a bold, peppery flavor that complements rich beef.

Variations often include shallots, garlic or mustard. This version uses shallot, garlic, bourbon, heavy cream and cracked black pepper. Because the steak is grilled, I reserve the resting juices and add them to the sauce instead of using beef broth, for extra beefy flavor.

What’s in the sandwich

This sandwich has six main components that work together:

• Bread: Ciabatta is a great choice — sturdy and thick enough to hold all the fillings.
• Arugula: Fresh, peppery greens add brightness and texture.
• Steak: New York Strip is used here, though filet or ribeye are excellent alternatives.
• Caramelized red onions: Deep, savory sweetness that balances the steak.
• Sautéed mushrooms: Earthy, savory mushrooms pair beautifully with the onions.
• Au poivre sauce: Creamy, peppery and rounded with bourbon — the centerpiece of the sandwich.

Can I substitute the alcohol?

If you prefer to avoid alcohol, substitute bourbon with apple juice or grape juice for a bit of sweetness and acidity. Another option is a bourbon-flavored extract to mimic the aroma without alcohol. Taste as you go when substituting, since the final flavor will differ slightly.

Caramelizing red onions

Thinly slice half a red onion. A mandolin speeds this up but be careful. Sauté the onions over medium-low heat in 1 tablespoon olive oil with a pinch of kosher salt, stirring occasionally. Cook low and slow for 30–40 minutes until very tender and deeply caramelized. About halfway through, add a splash of red wine and a little Worcestershire sauce, then continue cooking until soft and jammy.

Sautéing the mushrooms

Use pre-sliced baby bella mushrooms to save time. Sauté them in 1 tablespoon olive oil over medium heat until soft, about 5–10 minutes. Add a splash of soy sauce near the end and season with a pinch of kosher salt and cracked black pepper. Cook just until tender and well seasoned.

Cooking the NY Strip steak

I use the reverse sear method for even cooking: start the grill or smoker at 250°F and cook the steak until it’s about 15°F below your target internal temperature. This helps avoid burning and gives edge-to-edge doneness. Remove the steak, crank the heat to 500°F or higher, then sear 1–2 minutes per side until you reach the desired doneness. For medium-rare, pull at about 130°F and rest 10 minutes before slicing.

How to make au poivre sauce

Mince one shallot and one garlic clove. Sauté in a little olive oil over medium heat until fragrant, about 2 minutes. Lower the heat and add 2 tablespoons bourbon (or cognac/brandy) to deglaze the pan, scraping up any browned bits. Stir in 1/4 cup heavy cream, 1 teaspoon cracked black pepper and about 1 tablespoon of steak resting juices (or beef broth if you don’t have juices). Simmer until reduced by about one-third. The sauce will thicken as it cools; add a cornstarch slurry if you prefer a thicker finish.

Assembling the steak sandwich with au poivre sauce

Cut the ciabatta loaf lengthwise and into smaller portions if desired. Toast the cut sides in a pan with a little olive oil until golden. Spoon au poivre sauce onto the bottom half, then layer arugula, thinly sliced steak, caramelized red onions, sautéed mushrooms, and another spoonful of sauce. Cap with the top half of the bread.

This sandwich is loaded with complementary flavors and textures. It takes some time to prepare each component, but none of the steps are complicated. Customize to taste, then enjoy — one bite and you’ll know the effort paid off.

Ingredients

• 1 loaf ciabatta bread, cut lengthwise and in half as needed
• 8 oz New York Strip
• ¼ cup arugula
• 1.5 tablespoons kosher salt
• 1 tablespoon cracked black pepper
• 12 oz sliced baby bella mushrooms
• ½ red onion, thinly sliced
• 1 tablespoon soy sauce
• 2 tablespoons olive oil
• ¼ cup heavy cream
• 1 tablespoon Worcestershire sauce
• 2 tablespoons bourbon
• ¼ cup red wine
• 1 shallot, minced
• 1 clove garlic, minced
• 1 tablespoon steak juices (or 1 tablespoon beef broth)

Instructions

1. Slice half a red onion thinly. Cook in a pan over medium-low heat with 1 tablespoon olive oil and a pinch of kosher salt, stirring occasionally. Reduce heat if needed to prevent burning. Halfway through, add red wine and Worcestershire sauce. Continue to cook down until fully caramelized, about 30–40 minutes.
2. Sauté mushrooms in 1 tablespoon olive oil over medium heat until soft, about 5–10 minutes. Add soy sauce near the end, and season with salt and cracked black pepper to taste.
3. Season the NY Strip with 1 teaspoon kosher salt and cracked black pepper. Use the reverse sear method: cook at 250°F until the steak is about 15°F below your target temperature. Remove, increase the grill heat to 500°F or higher, and sear 1–2 minutes per side until done. For medium-rare, remove at 130°F and rest 10 minutes.
4. To make the au poivre sauce, sauté minced shallot and garlic in a little olive oil until fragrant. Add bourbon to deglaze, scraping up browned bits. Stir in heavy cream, 1 teaspoon cracked black pepper and the steak resting juices (or beef broth). Reduce until slightly thickened, about one-third. Remove from heat; it will thicken as it cools.
5. Toast the ciabatta in a pan with a little olive oil. Spread some au poivre sauce on the bottom half, then layer arugula, thinly sliced steak, caramelized onions, sautéed mushrooms and more sauce. Top with the other half of the bread.
6. Slice the assembled sandwich and serve. Share or enjoy the entire thing yourself.