Open-Faced Steak Sandwiches

Are you getting tired of making the same things for dinner? Try these open-faced steak sandwiches! Toasted French bread loaded with espresso-rubbed flank steak, slow-cooked caramelized onions, creamy horseradish sauce, and fresh chives. It looks like something from a restaurant, and it comes together faster than you'd think.

Why You'll Love This Recipe

• You can use a grill or a broiler. Both work well depending on the season and how cold it is outside.
• Everything can be prepped days ahead, making this stress-free for hosting.
• It works as a dinner, a heavy appetizer, or a buffet-style spread.
• Flank steak is a more affordable cut that delivers big flavor when cooked right and sliced correctly.
• It's beautiful on the plate and easy to scale up for a crowd.

Ingredients

Here are the ingredients needed to make open-faced steak sandwiches.

For the steak and toast:

• Flank Steak: A lean, flat cut with a strong grain that runs the length of the meat. Buy a piece that is about 1-inch- thick and close to 2 pounds. It's affordable and available at most grocery stores.
• Instant Espresso Powder: This is not ground coffee. Espresso powder dissolves into the rub and adds a subtle richness to the crust, not a coffee flavor. You'll find it in the baking aisle. My espresso rub works on other cuts too, and it's worth keeping on hand.
• French Bread: You want a loaf with a firm crust that can hold the weight of the toppings without getting soggy immediately. A standard French or Italian loaf from the bakery section works well.

The ingredient photos shown above are for a double batch. The recipe card reflects the standard serving for 4 people, so use that for your measurements.

For The Caramelized Onions And Horseradish Sauce

• Yellow Onions: Use yellow onions here. They have more bite when raw, which mellows beautifully over 40 to 45 minutes of slow cooking. Don't rush this step.
• Prepared Horseradish: Buy it in the jar, already prepared. Make sure to drain off the excess liquid before measuring. The sour cream base keeps the heat mild and the texture creamy.

See the recipe card below for all ingredient measurements.

How To Cut Bread At An Angle

For dinner, you want the largest surface area possible so each piece can hold more toppings. Cut the bread on the bias, at a 45-degree angle, rather than straight across.

1. Place the loaf on a cutting board and angle your serrated knife diagonally before slicing.
2. The result is an oval-shaped piece that is significantly wider than a straight cut would give you.
3. Aim for slices about 1 inch thick. These hold up under the weight of the steak and onions without going limp.

For appetizers, switch to a narrow baguette and cut straight across at a 90-degree angle to create small, round pieces that are easy to pick up without a fork.

How To Cut Steak Against The Grain

Flank steak is a tougher cut by nature, and slicing with the grain instead of against it will make it chewy even if it was cooked to the right temperature.

1. Look at the surface of your cooked flank steak and find the long parallel lines running through the meat. That is the grain.
2. Your knife needs to go perpendicular to those lines, not parallel.
3. The grain on flank steak does not always run in a perfectly straight line. It can angle across the cut. Keep adjusting your knife as you work down the steak so each slice stays perpendicular to those fibers.
4. Use a sharp 8-inch chef's knife and slice thin, about ¼ inch per slice. Thinner slices are easier to layer onto the bread and easier to eat.

Step-by-Step Instructions

Caramelize The Onions

Step 1: Preheat a 12-inch skillet over medium-high heat. Melt the butter, then add the paprika and kosher salt.

Add the sliced onions. Reduce the heat to medium. Let them cook and start stirring occasionally after 15 minutes. 

Step 2: Caramelized onions take 40 to 45 minutes to cook. Stir more frequently towards the end. Adjust the heat as needed to avoid burning them. You are looking for soft, translucent onions that have collapsed and turned golden. Remove from heat when done.

Make The Horseradish Sauce

Step 3: Mix the sour cream, drained horseradish, and black pepper in a small bowl. Taste it. If you want more heat, add more horseradish a teaspoon at a time. Set aside or refrigerate until ready to assemble.

Cook The Steak

Preheat your grill or broiler on high for 10 minutes. If using the broiler, position the oven rack so the steak will sit about 5 inches below the heating element.

Step 4: Whisk all the espresso rub ingredients together in a small bowl. Pat the flank steak dry with a paper towel, then sprinkle the rub evenly over both sides.

Step 5: Grill or broil the steak until the internal temperature reaches 130℉ for medium doneness, approximately 5 to 7 minutes per side. Pull it off the heat and let it rest for 5 minutes before slicing.

Watch for hot spots. Check the steak after the first few minutes and rotate or flip it as needed to get an even cook. You may need to flip it more than once to avoid burnt patches on one side.

Toast The Bread

Step 6: Using a serrated knife, slice the French bread at a 45-degree angle into 1-inch-thick pieces. Butter one side of each slice.

Step 7:  Lay the slices on a rimmed baking sheet, buttered side up. Broil for 1 to 2 minutes until lightly browned. Watch closely - it goes from golden to burnt quickly.

Assemble The Sandwiches

Step 8: Slice the rested flank steak against the grain into thin pieces, about ¼ inch thick.

Step 9: Spoon a layer of caramelized onions onto each slice of toasted bread. Layer 3 to 4 slices of steak on top. Add a generous spoonful of horseradish sauce and finish with chopped chives. Serve immediately.

Makes 2 open-faced sandwiches per person.

Make Ahead Instructions

This recipe is built for entertaining. Here's how to spread the work across a few days.

Up to 3 days ahead: Make the caramelized onions and horseradish sauce. Store both covered in the refrigerator. Make the espresso rub.

Day of, up to 2 hours ahead: Reheat the onions and cook the steak. Place it on a wire rack set over a rimmed baking sheet and leave it on the counter. Do not slice it yet. When you're ready to serve, rewarm the whole steak in a 250℉ oven to an internal temperature of 110℉, about 15 to 20 minutes, then slice.

Bread: Slice the bread and lay the buttered pieces on a rimmed baking sheet. Cover with aluminum foil until you're ready to broil. You can broil the bread up to 30 minutes ahead of serving and cover with foil to keep it from drying out.

By the time guests arrive, you are toasting bread and slicing steak. That's it. The main dishes category has more recipes that follow this same make-ahead logic if you're building out a full menu.

Storage & Reheating Information

Open-faced steak sandwiches are best eaten right after assembling. Once the bread has toppings on it, it will soften.

Steak: Store leftover sliced steak covered in the refrigerator for up to 3 days. Reheat gently in the microwave in 20-second increments or warm in a 300℉ oven until warm to the touch. Flank steak toughens when overheated, so go slow.

Caramelized onions: Store covered in the refrigerator for up to 4 days. Reheat in a microwave in 20-second increments or a small skillet over low heat.

Horseradish sauce: Store covered in the refrigerator for up to 3 days. Stir before using.

Bread: Store in a Ziploc bag at room temperature for up to 2 days. Reheat slices in a toaster.

Do not freeze assembled sandwiches, caramelized onions, or horseradish sauce.

FAQ

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