Roast Beef Sandwiches with Caramelized Onion
Elevate your sandwich game with these irresistible Roast Beef Sandwiches with Caramelized Onion—a gourmet treat that's easy enough for a weeknight meal yet impressive enough for entertaining. Tender, thinly sliced roast beef is warmed to perfection and layered with sweet, golden-brown caramelized onions, which are cooked slowly with butter, olive oil, and a touch of brown sugar for an indulgently rich flavor. A crisp toasted baguette forms the base, while a creamy blend of whole-grain mustard and mayonnaise adds a tangy twist. Optional additions like melted Swiss cheese and peppery arugula provide customizable flair. Ready in under an hour, this hearty sandwich is ideal for lunch, dinner, or any occasion that calls for comforting sophistication.
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Recipe Information
Ingredients
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 2 large yellow onions
- 0.5 teaspoon salt
- 0.25 teaspoon black pepper
- 1 teaspoon brown sugar
- 1 large baguette
- 0.75 pound roast beef (sliced thin)
- 4 slices Swiss cheese (optional)
- 3 tablespoons whole-grain mustard
- 3 tablespoons mayonnaise
- 1 cup arugula (optional)
Instructions
Peel and thinly slice the onions.
In a large skillet, heat butter and olive oil over medium heat.
Add the onions, salt, and pepper to the skillet and stir to combine.
Cook the onions, stirring occasionally, for 20-25 minutes, or until they become soft and golden brown. If they start to stick, add a splash of water to the skillet.
In the last 5 minutes of cooking, stir in the brown sugar to enhance the sweetness of the onions.
While the onions are caramelizing, preheat your oven to 375°F (190°C) and slice the baguette into four equal portions.
Split each portion of the baguette lengthwise and toast them in the oven for 5-7 minutes, or until lightly crisped.
In a small bowl, mix the whole-grain mustard and mayonnaise until well combined. Spread the mixture evenly on the inside of each toasted baguette piece.
Heat the sliced roast beef briefly in the skillet to warm it up, about 2-3 minutes.
Layer the warmed roast beef onto the bottom half of each baguette.
Top the roast beef with caramelized onions and a slice of Swiss cheese, if using.
Place the sandwiches under the oven broiler for 1-2 minutes, just enough to melt the cheese.
Add a handful of arugula on top, if desired, and close the sandwich with the top half of the baguette.
Serve warm and enjoy your roast beef sandwiches with caramelized onions!
Nutrition Facts
Calories |
665 | ||
|---|---|---|---|
% Daily Value* |
|||
| Total Fat | 32.7 g | 42% | |
| Saturated Fat | 12.7 g | 64% | |
| Polyunsaturated Fat | 0.0 g | ||
| Cholesterol | 104 mg | 35% | |
| Sodium | 1386 mg | 60% | |
| Total Carbohydrate | 52.7 g | 19% | |
| Dietary Fiber | 4.2 g | 15% | |
| Total Sugars | 5.1 g | ||
| Protein | 39.6 g | 79% | |
| Vitamin D | 0.2 mcg | 1% | |
| Calcium | 314 mg | 24% | |
| Iron | 4.5 mg | 25% | |
| Potassium | 574 mg | 12% | |
*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
