| Total: | 1 hr 30 min |
| Prep: | 1 hr 30 min |
| Yield: | 6 main-course servings |
Ingredients
- 1 medium red onion, halved and thinly sliced
- 1 tablespoon, plus 2 teaspoons kosher salt, plus more to taste
- 6 tablespoons red wine vinegar
- 3/4 cup mayonnaise
- 3/4 cup sour cream
- 1/4 cup plus 2 tablespoons jarred grated horseradish (with liquid)
- 1/2 teaspoon grated lemon zest
- Freshly ground black pepper
- Hot sauce
- 6 Kaiser rolls
- 12 slices vine-ripened tomatoes
- 24 ounces freshly sliced rare roast beef
- 3 loosely packed cups watercress or arugula, or a combination of both
Instructions
- In a small bowl, mix together the onion and 1 tablespoon of the salt. Set aside for 20 minutes. Rinse the onions with cold running water. Drain and squeeze to remove excess liquid. Combine the onions and the vinegar and marinate at least 30 minutes or up to 24 hours.
- In a small bowl, mix together the mayonnaise, sour cream, horseradish, zest, and 2 teaspoons salt. Season generously with pepper and hot sauce to taste. Refrigerate the horseradish sauce for at least 30 minutes.
- Preheat the broiler. Slice the rolls in half lengthwise. Using your hands, shallowly scoop out the inside of each half. Transfer the rolls to a baking sheet and arrange scooped-side up. Toast the rolls under the broiler for about 1 minute. Slather the inside of the rolls with the horseradish sauce. On each of the roll bottoms, layer 2 tomato slices and season with salt and pepper to taste. Top the tomatoes with some of the roast beef overlapped into “ruffles” and season with salt and pepper. Top the meat with some of the onions and watercress and cover with the tops of the roll. Serve immediately.
Nutrition Facts
| Serving Size | 1 of 6 servings |
| Calories | 679 |
| Total Fat | 44 g |
| Saturated Fat | 12 g |
| Carbohydrates | 37 g |
| Dietary Fiber | 3 g |
| Sugar | 5 g |
| Protein | 31 g |
| Cholesterol | 111 mg |
| Sodium | 810 mg |
Reviews
This recipe was delicious and a great summer sandwich! Boars Head Seasoned Filet is a good medium rare for these sandwiches. Whole Foods also has a good rare roast beef in there deli. We added extra horseradish to make the horseradish spread spicier. Other than that- it was perfect as directed!
Really delicious! the key to a great roast beef sandwich is that the meat is medium rare, otherwise it’s too dry. Made this on a whole wheat sesame loaf of Italian bread and made as stated, except I added some roasted peppers and avocado. Let the sauce and onions marinate as stated because they really compliment each other. Great!!
Good sandwich. Really enjoyed the onions in red wine vinegar
Super yummy! I used left-over meat from a pot roast I had made a few days before and it worked out wonderfully!
I made these for the first time, they are great!! Decreased the salt to 1 tsp. which made the sauce outstanding. Also added blue cheese. These would be perfect for a party.
Great to make minature sandwiches for parties. I’ve had raving reviews on the sauce. Another great substition for tomatoes is roasted red peppers.
The horseradish sauce with the lemon zest really made this sandwich special. I served them open-faced on sliced bagette. They were really well received!