French dip sandwiches

Ingredients:

Onion spread

• 3 tablespoons of vegetable oil
• 1 large onion, thinly sliced
• 6 medium shallots, thinly sliced
• 2 bunches green onions, chopped (white parts separated from green parts)
• 1.5 cups sour cream
• 1 cup mayonnaise
• 2 tsp white wine vinegar
• 2 tsp Worcestershire sauce

Sandwiches

• 6 cloves of garlic
• 1 teaspoon extra-virgin olive oil
• 0.5 tsp celery salt
• A pinch of cayenne pepper
• 1 beef eye-round cut weighing 1.3-1.8 kg.
• 4 cups lightly salted beef broth
• 2 stalks celery, coarsely chopped
• 1 small onion, coarsely chopped
• 3 sprigs of parsley
• 2 tablespoons unsalted butter
• 2 tbsp. flour
• 2 tsp dry sherry
• 6 Italian rolls, 6 inches long, halved at the ends and lightly toasted

Preparation:

1. Onion spread:
   
   Heat the vegetable oil in a large skillet over medium-low heat. Add the onion and a pinch of salt, cover, and sauté, stirring, until golden, about 35 minutes. Add the shallots and white parts of the green onions; cover and cook, stirring, until the onions are golden, about 25 minutes more. Add the green onions, then remove from heat and let cool.
2. Chop the onion mixture and transfer to a bowl. Add sour cream, mayonnaise, vinegar, Worcestershire sauce, and 1 teaspoon of salt. Cover and refrigerate for at least 2 hours and up to 24 hours.
3. Prepare beef for sandwiches:
   
   Mince the garlic, then sprinkle with 1 teaspoon of salt and mash with the flat side of a large knife until it forms a paste. Transfer to a bowl; add olive oil, celery salt, cayenne pepper, and 1/2 teaspoon of black pepper. Use a knife to make small slits all over the beef, then use your fingers to press the garlic paste into the slits. Cover and refrigerate for at least 1 hour or overnight.
4. Preheat oven to 425°F (220°C). Bring beef to room temperature. Season with 2 teaspoons salt and 1/2 teaspoon black pepper. Place meat on a rack in a roasting pan; add 1 cup broth, 3/4 cup water, celery, onion, and parsley to the pan. Roast for 10 minutes, then reduce oven temperature to 350°F (175°C) and roast until a thermometer inserted into the center of the beef reads 115°F (46°C), about 45 minutes more. Transfer meat to a cutting board; let rest for 20 minutes. Strain any juices from the roasting pan and set aside.
5. Meanwhile, prepare the sauce.:
   
   In a medium saucepan over medium heat, melt the butter. Add the flour and cook, stirring, for 1 minute. Stir in the pan juices and the remaining 3 cups of broth and bring to a simmer, stirring constantly. Remove from the heat and add the sherry.
6. Spread a little onion spread on the buns. Thinly slice the beef against the grain. Dip the meat in the sauce, then layer it on the buns. Serve the sandwiches with the remaining sauce for dipping.