Preheat your oven to 325°F (163°C). Season the beef roast generously with salt and black pepper. Place the beef in a roasting pan and roast in the preheated oven for 1.5 to 2 hours, or until it reaches your desired doneness (medium-rare is recommended). Remove from the oven and let it rest for at least 15 minutes before slicing thinly.

Boursin Cheese Horseradish Spread Preparation

Make the Spread

In a small bowl, mix together the Boursin cheese, prepared horseradish, and finely chopped chives until well combined. Set aside.

Au Jus Preparation

Prepare the Au Jus

In a saucepan over medium heat, add the chopped onion and minced garlic. Sauté until the onion is translucent, about 5 minutes. Add the beef broth and soy sauce, and bring to a simmer. Season with black pepper to taste. Reduce the heat to low and let it simmer for 10 minutes.

Assembly

Assemble the French Dip

Slice the French rolls in half. Spread a generous amount of the Boursin cheese horseradish spread on the inside of each roll. Layer the sliced roast beef on top and add a slice of Swiss cheese. Place the sandwiches under the broiler for 2-3 minutes or until the Swiss cheese is melted and bubbly.

Serve

Serve the assembled sandwiches with a side of warm au jus for dipping.