Introduction
This hearty recipe combines the earthy flavors of roasted parsnips and carrots with savory onions, succulent roast beef, and a decadent melted cheese topping. Served as sandwiches, these delightful creations are perfect for a cozy meal any time of year. With just a few simple ingredients, you can whip up a comfort dish that’s sure to please.
Detailed Ingredients with measures
3 parsnips
6 carrots
Olive oil
2 sprigs of fresh rosemary
3 onions
1 knob of unsalted butter
180g Cheddar cheese
3 teaspoons English mustard
12 slices of bread
400g sliced leftover roast beef
Prep Time
20 minutes
Cook Time
40 minutes
Total Time
1 hour
Yield
6 servings
Method
1. Preheat the oven to 200ºC/400ºF/gas 6.
2. Wash the parsnips and carrots, trim, and chop them into even-sized chips.
3. Place the chopped vegetables in a large roasting dish with 1 tablespoon of olive oil and a pinch of sea salt.
4. Strip in the rosemary leaves and mix well.
5. Roast the vegetables for 20 to 25 minutes, or until golden and cooked through.
6. Peel and finely slice the onions.
7. Place the sliced onions in a non-stick frying pan over medium-low heat with 1 tablespoon of olive oil.
8. Cover and cook the onions for 10 to 15 minutes, or until soft and sweet, stirring occasionally.
9. Stir in the butter for added richness, then transfer the onions to a bowl.
10. Return the frying pan to the heat and grate the cheese into it.
11. Add the mustard to the pan and let the mixture melt together.
12. Toast the bread slices.
13. Line up 6 slices of toasted bread and divide the cooked onions evenly among them.
14. Lay the sliced roast beef over the onions.
15. Pour the bubbling, melted cheese mixture over the beef.
16. Top each sandwich with the remaining slices of toasted bread.
17. Slice the sandwiches in half and serve with the roasted root vegetable chips on the side.
Detailed Directions and Instructions
Step 1: Preheat the Oven
Preheat the oven to 200ºC/400ºF/gas 6.
Step 2: Prepare the Vegetables
Wash the parsnips and carrots thoroughly. Trim their ends and chop them into even-sized chips to ensure uniform cooking.
Step 3: Coat the Vegetables
Place the chopped parsnips and carrots in a large roasting dish. Drizzle with 1 tablespoon of olive oil and add a pinch of sea salt.
Step 4: Add Rosemary
Strip the leaves from the fresh rosemary sprigs and add them to the vegetables. Mix well to ensure the veggies are evenly coated.
Step 5: Roast the Vegetables
Roast the vegetables in the preheated oven for 20 to 25 minutes, or until they are golden brown and cooked through.
Step 6: Slice the Onions
Peel the onions and slice them finely.
Step 7: Cook the Onions
In a non-stick frying pan, heat 1 tablespoon of olive oil over medium-low heat. Add the sliced onions, cover the pan, and cook for 10 to 15 minutes, stirring occasionally, until the onions are soft and sweet.
Step 8: Add Butter to the Onions
Stir the knob of unsalted butter into the cooked onions for added richness. Once melted, transfer the onions to a bowl and set aside.
Step 9: Prepare the Cheese Mixture
Return the frying pan to the heat and grate the Cheddar cheese directly into it. Add the English mustard and allow the mixture to melt together, stirring occasionally.
Step 10: Toast the Bread
Toast the slices of bread until they are golden and crispy.
Step 11: Assemble the Sandwiches
Line up 6 slices of toasted bread. Evenly distribute the cooked onions on top of the bread.
Step 12: Add Roast Beef
Lay the sliced leftover roast beef over the onions on each sandwich.
Step 13: Pour Cheese Mixture
Pour the bubbling, melted cheese mixture over the roast beef on each sandwich.
Step 14: Top the Sandwiches
Place the remaining slices of toasted bread on top of the sandwiches to complete them.
Step 15: Serve the Sandwiches
Slice each sandwich in half and serve with the roasted root vegetable chips on the side.
Notes
Equipment Needed
A roasting dish, a non-stick frying pan, a spatula, and a toaster are required for this recipe.
Ingredient Substitutions
Feel free to substitute the Cheddar cheese with any cheese of your preference if desired. You can also replace the roast beef with turkey or any other leftover meat.
Serving Suggestions
These sandwiches make a great meal on their own, but you can also serve them with a fresh salad or pickles for added crunch.
Storage Instructions
Leftover sandwich ingredients can be stored separately in an airtight container in the refrigerator for up to 2 days. Reassemble and heat the sandwiches before serving.

Cook techniques
Roasting
Roasting vegetables in the oven at a high temperature allows for caramelization, enhancing their natural sweetness. Ensure even-sized chips for consistent cooking.
Sautéing
Sautéing onions over medium-low heat helps to slowly develop their sweetness. Cover the pan initially to trap moisture, then stir occasionally to ensure even cooking.
Melting
Melting butter with cheese allows for a rich, creamy texture that enhances the flavor. Combine with mustard for a tangy addition.
Toasting
Toasting bread adds a crunchy texture and a warm base for your sandwich. Ensure each slice is evenly toasted for the best outcome.
Layering
Layering the ingredients thoughtfully in the sandwich ensures that each bite has a balance of flavors and textures, with the beef and onions complementing the melted cheese.
FAQ
Can I use other vegetables for roasting?
Yes, you can substitute other root vegetables such as sweet potatoes or turnips.
What type of cheese can I use instead of Cheddar?
You can use Gruyère, mozzarella, or any other melting cheese if you prefer.
How can I make the onions sweeter?
You can add a pinch of sugar while sautéing the onions to enhance their sweetness.
Can I prepare this dish ahead of time?
Yes, you can prepare the roasted vegetables and sautéed onions in advance and assemble the sandwiches when ready to serve.
Is there a vegetarian option for this recipe?
Yes, you can replace the roast beef with roasted mushrooms or grilled vegetables for a vegetarian version.
Conclusion
This delicious sandwich, complemented by roasted root vegetable chips, combines the sweetness of caramelized onions and the savory richness of melted cheddar cheese, making it a hearty and satisfying meal. The use of leftover roast beef adds an element of practicality, enabling you to minimize food waste while enjoying a comforting dish. The aromatic rosemary enhances the flavor of the roasted vegetables, bringing everything together beautifully.
More recipes suggestions and combination
Parsnip and Carrot Mash
Boil parsnips and carrots until soft, then mash with butter and a pinch of salt for a creamy side dish.
Roasted Vegetable Soup
Blend roasted parsnips and carrots with vegetable broth and seasonings to create a warm, comforting soup.
Cheddar and Mustard Toasted Sandwiches
Use the cheese and mustard to make toasted sandwiches, adding slices of tomato or pickles for extra flavor.
Vegetable Frittata
Incorporate leftover roasted vegetables into a frittata with eggs and cheese for a filling breakfast or brunch option.
Roast Beef Salad
Toss the sliced roast beef with fresh greens, a mustard vinaigrette, and roasted carrots for a light yet satisfying meal.
