These open-face pot roast sandwiches pack serious flavor into a simple, fast meal. Thick slices of hearty toast get a generous smear of herbed mayonnaise, a layer of sweet, stewed onions, tender slices of leftover pot roast (or deli roast beef), and a blanket of thinly sliced gruyère. After a quick broil to melt the cheese, the sandwiches are finished with a pile of dark leafy greens for a bright contrast in texture and color.
This is an excellent way to use up leftovers and have dinner on the table quickly—most of the hands-on work is in toasting and assembling, and the sandwiches take only a few minutes under the broiler to finish. They make a satisfying lunch or an easy weeknight supper when you want something hearty without a lot of fuss.
Open Face Pot Roast Sandwiches (Pot roast tartines)
If you don’t have leftover pot roast, deli roast beef makes a perfectly good substitute and shortens the prep time. The recipe is forgiving: swap herbs, use different cheese, or switch the bread to fit what you have on hand. I like to serve these sandwiches with a crisp salad—Israeli salad is a favorite—but golden French fries are a classic and delicious option as well.
Recipe
Pot Roast Sandwiches
Pot roast sandwiches are an easy, flavorful way to transform leftovers into a quick meal. With caramelized onions, herbed mayo, gooey gruyère, and fresh greens, they balance savory richness with bright, fresh elements.
20 minutes
10 minutes
30 minutes
Ingredients
- 1 large yellow onion
- 2 tablespoons vegetable, canola, or extra virgin olive oil
- 4 thick slices of hearty bread (sourdough works well)
- ¾ cup mayonnaise
- 1 teaspoon minced garlic
- ⅓ cup fresh parsley, finely chopped
- ⅓ cup fresh cilantro, finely chopped
- 16–20 ounces leftover pot roast — or 1 pound deli roast beef
- 8 ounces gruyère cheese, sliced very thin
- 4 cups dark leafy greens, like spinach or kale
Instructions
- Preheat your oven’s broiler.
- Cut the yellow onion in half, remove the papery outer layers, and slice into roughly ¼-inch slices. Heat 2 tablespoons of oil in a large skillet over medium heat. Add the onions and cook, stirring often, until they are soft and lightly golden. Transfer to a plate and let cool slightly.
- Toast the bread slices and arrange them side by side on a baking sheet.
- Mix the mayonnaise with the minced garlic, chopped parsley, and chopped cilantro. Spread a generous layer of this herbed mayonnaise on each slice of toasted bread.
- Top each slice with a layer of the sautéed onions, followed by slices of pot roast or deli roast beef. Add a few thin slices of gruyère on top.
- Place the baking sheet under the broiler just long enough to melt and lightly brown the cheese. Watch closely—cheese can go from perfect to burnt very quickly.
- Remove from the oven, transfer the sandwiches to plates, and finish each with a generous handful of kale, spinach, or other dark leafy greens. Serve immediately.
Notes and Variations
For extra flavor, warm the leftover pot roast briefly in its juices or a splash of beef broth before assembling. Swap gruyère for Swiss, cheddar, or fontina if you prefer. If using sturdier greens like kale, consider massaging them with a little olive oil and lemon juice to soften them slightly. To make this vegetarian, substitute roasted mushrooms or a thick slice of roasted eggplant for the meat and use a vegetarian mayo.
These sandwiches are best served the day you assemble them, but components can be prepped in advance: caramelize the onions and keep them refrigerated, mix the herbed mayo ahead of time, and slice the cheese and roast before you’re ready to assemble.
Nutrition Information
Yield: 4 Serving Size: 1 sandwich
Amount Per Serving (approximate):
Calories: 740 · Total Fat: 58g · Saturated Fat: 18g · Cholesterol: 138mg · Sodium: 1719mg · Carbohydrates: 14g · Fiber: 4g · Sugar: 4g · Protein: 42g