This ultimate roast beef sourdough sandwich is the best way to transform leftover tender eye of round roast or bottom round roast into a gourmet farmhouse lunch served in a sourdough ciabatta rolls!
The Best Ingredients for a Sourdough Roast Beef Sandwich
The secret to a world-class sandwich isn’t just the toppings; it’s the quality of the individual components. Here is what you’ll need from the farmhouse kitchen:
- Sourdough Ciabatta Rolls: These are the ultimate vessel. The open crumb (those lovely air pockets) catches the sauce, while the sturdy crust holds up to the juicy roast beef.
- Leftover Roast Beef: I recommend using thinly sliced Tender Eye of Round or my Garlic & Herb Rump Roast Recipe. The leaner the slice, the better it piles up!
- Horseradish Avocado Mayo: This is a game-changer. I mix my homemade avocado oil mayo with a generous tablespoon of prepared horseradish for a creamy, heart-healthy spread with a signature kick.
- Garden Fresh Toppings: Crisp green leaf lettuce, juicy tomato slices, and thinly sliced red onions for that essential crunch and bite.
Which Sourdough Bread is Best for Roast Beef?
I used my Sourdough Ciabatta Rolls for this specific recipe because of their incredible “sauce-catching” texture, but this sandwich is versatile! Here are a few other farmhouse favorites that also go great:
- Soft Sourdough Sandwich Bread: If you prefer a classic, easy-to-bite sandwich that kids love, this is the one. It’s sturdy enough for the beef but soft on the crust.
- Sourdough Baguettes: For a “French Dip” style experience, a crusty baguette is the way to go. It provides a satisfying crunch that contrasts perfectly with the tender meat.
- Simple Sourdough Bread (Artisan Loaf): If you have a round boule on the counter, thick toasted slices of a traditional artisan loaf make for a rustic, open-faced roast beef melt that is to die for.
Tips for the Perfect Sourdough Roast Beef Sandwich
After making hundreds of these sandwiches on the farm, I’ve learned a few tricks to ensure every bite is perfect. Here is how to take yours to the next level:
- Slice Roast Beef Against the Grain: When slicing your Eye of Round or Rump Roast, always cut against the muscle fibers. This ensures the beef is “melt-in-your-mouth” tender and easy to bite through in a sandwich.
- The “Barrier” Layer: To prevent your Sourdough Ciabatta from getting soggy, always place your lettuce leaf directly against the bottom bun. It acts as a shield against the tomato juices and mayo!
- Temperature Matters: For the best flavor, let your cold leftover roast beef sit on the counter for about 10–15 minutes before assembling. Room-temperature beef has much more depth of flavor than meat pulled straight from the fridge.
- Toast for Texture: I highly recommend a light toast on the cut side of your sourdough. It provides a satisfying “crunch” that stands up to the creamy horseradish avocado mayo.
Ultimate Roast Beef Sourdough Sandwich (using leftovers!)
This Ultimate Roast Beef Sourdough Sandwich is the best way to use leftover roast beef. With crusty, toasted Sourdough Ciabatta Rolls, horseradish avocado mayo, and layers of tender roast beef! It's a gourmet lunch that comes together in just 10 minutes.
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Servings: 4 servings
Calories: 472kcal
Ingredients
- 4 Sourdough Ciabatta Rolls halved
- 1 – 1.5 lbs Eye of round roast or Rump Roast Leftover
- 1/2 cup Avocado Oil Mayo Homemade is best!
- 2 tbsp Prepared Horseradish adjust to your heat preference
- 1 large Tomato sliced into 8 rounds
- 1/2 Red Onion thinly sliced
- 4 large Green Leaf Lettuce leaves washed and cut leaves in half
Instructions
- Prepare Spread: In a small bowl, whisk together the homemade avocado mayo and the prepared horseradish until smooth. Set aside.
- Toast Rolls: Half the Sourdough Ciabatta Rolls and place them cut-side up under a broiler for 1-2 minutes or face-down in a buttered skillet until golden and crisp.
- Spread a generous layer of the horseradish mayo on both the top and bottom of each toasted roll.
- Layer: Place a leaf of lettuce on the bottom half of each roll. This "farmhouse secret" prevents the bread from getting soggy from the beef and tomatoes.
- Beef: Divide the sliced roast beef evenly among the four rolls, piling it high for a hearty look.
- Toppings: Top the beef with two slices of tomato and a few rings of red onion. Season the tomatoes with a pinch of salt and pepper if desired.
- Serve: Close the sandwiches and serve immediately while the rolls are still warm and the toppings are crisp.
Notes
Slicing the Beef: For the most tender bite, ensure your leftover Eye of Round or Rump Roast is sliced very thin and strictly against the grain. If you see long muscle fibers, turn the roast 90 degrees before slicing. This breaks up the connective tissue so the meat melts in your mouth.
Warming Tip: If you prefer a warm sandwich, don’t microwave the beef (it will make it rubbery!). Instead, place the slices in a skillet with a tablespoon of leftover au jus or beef broth over low heat for just 60 seconds until barely warmed through.
Bread Choices: While Sourdough Ciabatta is my top pick for its “sauce-trapping” pockets, you can easily swap it for toasted slices of my Soft Sourdough Sandwich Bread or a crusty Sourdough Baguette.
Make-Ahead: If packing this for a lunch, keep the horseradish mayo in a small separate container and apply it just before eating to keep your sourdough perfectly crisp.
Nutrition
Serving: 1g | Calories: 472kcal | Carbohydrates: 31g | Protein: 30g | Fat: 25g | Saturated Fat: 5g | Polyunsaturated Fat: 13g | Monounsaturated Fat: 6g | Trans Fat: 0.1g | Cholesterol: 76mg | Sodium: 2193mg | Potassium: 469mg | Fiber: 2g | Sugar: 3g | Vitamin A: 398IU | Vitamin C: 60mg | Calcium: 332mg | Iron: 3mg
About Juliea
Juliea is a mother of six, a sourdough baker, and a homestead builder living in Idaho. Alongside her husband and their horse, Dude, she manages a busy farmhouse and shares her love for scratch-cooking and simple homemaking. Through her blog and YouTube channel, she helps millions of families every year master the art of the handmade home.
