Gusto TV Roast Beef Dip with Horseradish Sauce Recipe - A Savoury, Gourmet Sandwich

Roast Beef Dip with Horseradish Sauce Recipe

This Roast Beef Dip with Horseradish Sauce is a restaurant-quality sandwich elevated with bold herbs, creamy heat, and rich homemade au jus. Created by host Lauren Gulyas, this recipe delivers tender, perfectly seared beef tenderloin layered onto soft panini buns, topped with melted mozzarella, sharp Dijon mustard, and finished with a bright, creamy horseradish sauce.

Served alongside a warm rosemary-thyme au jus for dipping, this sandwich strikes the perfect balance between indulgent comfort food and refined flavor. Whether you’re hosting a casual dinner party, planning a game day spread, or craving a hearty gourmet sandwich, this recipe transforms simple ingredients into something memorable.

The Inspiration

This Roast Beef Dip with Horseradish Sauce was inspired by the classic French dip sandwich — a beloved bistro staple known for thinly sliced beef served on warm bread with savory jus for dipping. Host Lauren Gulyas wanted to elevate that comforting favorite by using premium beef tenderloin, fresh herbs, and a bold, from-scratch horseradish cream that adds brightness and balance.

Traditional French dip sandwiches often rely on deli-style roast beef and simple broth. In this version, Lauren builds deeper flavor by first searing the beef to create a caramelized crust, then finishing it in the oven for precise doneness. The pan drippings become the base of a rosemary- and thyme-infused au jus, transforming a simple dipping sauce into something aromatic and layered.

Ingredients

Horseradish Sauce

¼ cup (60ml) peeled and rougly chopped fresh horseradish root,
2 tablespoons (30ml) white wine vinegar
½ cup (120ml) mayonnaise
½ cup (120ml) sour cream
Juice of 1 small lemon
Salt and pepper

Method

Place horseradish in a food processor, and blend until coarse.
Add white wine vinegar, and blend until slightly smooth.
Add mayonnaise and sour cream, and blend until smooth.
Add lemon juice, salt, and pepper.
Blend until smooth.
Reserve Horseradish Sauce for later use.

Ingredients

Roast Beef Dip with Horseradish Sauce

3 tablespoons (45ml) olive oil
1 lb. (450g) beef tenderloin, trimmed
2 tablespoons (30ml) butter
2 tablespoons (30ml) all-purpose flour
2 cups (480ml) beef stock
1 tablespoon (15ml) fresh rosemary, chopped
1 tablespoon (15ml) fresh thyme, chopped
4 soft Panini buns
½ cup (120ml) Dijon mustard
8 large slices mozzarella cheese
Salt and pepper

Method

Preheat oven to 375 degrees Fahrenheit.
Heat oil in a medium size skillet over medium-high heat.
Season beef with salt and pepper.
Place beef in hot skillet, and sear for 3-4 minutes per side.
To cook beef to medium-rare, transfer skillet with beef to the oven and cook for 12-15 minutes.
Keep oven preheated for later use.
Let beef rest on cutting board for 10 minutes before slicing.
Transfer beef drippings and stock to a medium saucepan and stir in butter.
Heat over medium-high heat.
Stir in flour and cook for 1 minute.
Add beef stock, rosemary and thyme to the pan and bring to a simmer.
Simmer for 10-12 minutes, until slightly thickened.
Keep au jus sauce warm until ready to serve.
Slice beef thinly while still warm.
Slice Panini buns and spread Dijon mustard on the bottom half of the bun.
Top bread with sliced beef and cheese.
Spread reserved Horseradish Sauce onto the top half of the Panini bun and place it onto the sandwich.
Transfer sandwiches to a parchment-lined baking tray and heat sandwiches in the oven for 6-8 minutes, or until sandwiches are hot and cheese has melted.
Serve sandwiches hot, with warm au jus sauce on the side.

Serving Suggestions

This Roast Beef Dip with Horseradish Sauce is a rich, savory sandwich that benefits from thoughtful pairings to create a balanced and satisfying meal. Because the beef tenderloin is tender and juicy, the mozzarella adds creaminess, and the horseradish sauce delivers a bright, tangy heat, lighter and fresher accompaniments work beautifully to contrast the richness.

A simple arugula salad tossed in a lemon vinaigrette provides a peppery bite and acidity that cuts through the buttery au jus and melted cheese. Mixed greens with shaved fennel and thinly sliced apple offer both crunch and subtle sweetness, enhancing the herbaceous rosemary and thyme notes in the dipping sauce. Pickled vegetables or crisp cornichons are also excellent additions, as their acidity sharpens each bite of the sandwich and refreshes the palate between dips.

Final Thoughts

Lauren Gulyas’ Roast Beef Dip with Horseradish Sauce from A is for Apple 2 transforms a classic sandwich into a gourmet centerpiece. The combination of tender beef tenderloin, melted mozzarella, tangy Dijon, creamy horseradish sauce, and herb-infused au jus creates a sandwich that feels indulgent yet refined.

Perfect for entertaining or upgrading your weeknight dinner routine, this recipe proves that comfort food can still be elegant and full of fresh, vibrant flavor.

If you’re looking for a bold, satisfying sandwich that impresses every time, this roast beef dip belongs in your rotation.

Find more recipes from A is for Apple here!