These open-face pot roast sandwiches are packed with savory flavor and are a fantastic way to transform leftover pot roast into a quick, satisfying meal. Thick slices of sturdy toast are spread with an herbed mayonnaise, topped with sweet, slowly-cooked onions, tender pot roast (or deli roast beef if you don’t have leftovers), and thin slices of gruyère cheese. A handful of dark leafy greens such as kale or spinach finishes each tartine for a fresh contrast.
This recipe comes together quickly—about 15–30 minutes depending on how much prep you need—and makes an excellent weeknight dinner, a casual weekend lunch, or an indulgent snack. The combination of caramelized onions and melted gruyère is classic and comforting, while the herbed mayonnaise adds a bright, herbaceous lift that ties everything together.
Open Face Pot Roast Sandwiches (Pot roast tartines)
If you don’t have leftover pot roast on hand, deli roast beef is an excellent substitute and keeps this recipe fast and accessible. I often serve these sandwiches with Israeli salad for brightness, but French fries or a simple green salad are great options too—pick what you and your family enjoy most.
📖 Recipe
Pot Roast Sandwiches
These tartines are a terrific way to use leftover pot roast and to assemble a flavorful dinner in about 15 minutes. They balance rich, meaty notes with sweet caramelized onions and fresh herbs.
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, chopped fine
- ⅓ cup fresh cilantro, chopped fine
- 16–20 ounces leftover pot roast or 1 pound deli roast beef
- 8 ounces gruyère cheese, sliced very thin
- 4 cups dark leafy greens, such as spinach or kale
Instructions
- Preheat your oven’s broiler and position a rack a few inches from the heat source.
- Halve the onion, remove the papery outer layers, and slice into ¼-inch-thick slices. Heat 2 tablespoons oil in a large skillet over medium heat. Add the onion and cook, stirring frequently, until the slices are soft and lightly golden brown—this may take 8–12 minutes. Caramelized onions add sweetness and depth, so cook until the edges begin to brown but do not burn. Transfer the onions to a plate and let cool slightly.
- Toast the bread slices until slightly crisp and arrange them on a baking sheet lined for broiling.
- In a small bowl, combine the mayonnaise, minced garlic, chopped parsley, and chopped cilantro. Taste and adjust salt or herbs as desired. Spread a generous layer of the herbed mayonnaise on each toasted slice of bread.
- Top each toast with a layer of caramelized onions, then distribute the sliced pot roast or deli roast beef evenly. Add a few thin slices of gruyère over the meat.
- Place the baking sheet under the broiler just long enough to melt and lightly brown the cheese—watch closely, as cheese can go from golden to burnt very quickly.
- Remove the tartines from the oven, top each with a generous handful of dark leafy greens (torn or roughly chopped), and transfer to plates. Serve immediately with your preferred side.
Tips, Variations & Serving Suggestions
For a richer flavor, use a day-old or slightly stale bread so it holds the toppings better. If you prefer, briefly sauté the greens with a touch of oil and garlic before topping the sandwich for a warm, wilted finish. Try swapping gruyère for Swiss, fontina, or provolone if you want a milder or more melty cheese.
Leftover pot roast works beautifully here, but thinly sliced roast beef, leftover brisket, or even shredded rotisserie chicken can be used in a pinch. If you like more tang, add a squeeze of lemon or a drizzle of vinaigrette over the greens before serving.
Serve with a light salad such as Israeli salad, roasted vegetables, or fries for a heartier meal. These open-face sandwiches make excellent leftovers when stored in an airtight container in the refrigerator; reheat gently in a low oven to preserve texture.
Nutrition Information
Yield:
4
Serving Size:
1
Amount Per Serving:
Calories: 740
Total Fat: 58g
Saturated Fat: 18g
Cholesterol: 138mg
Sodium: 1719mg
Carbohydrates: 14g
Fiber: 4g
Sugar: 4g
Protein: 42g